2210 GMT: It is now after midnight in Egypt, and we are taking a few hours' break. We leave you for the moment with this image from tonight in Tahrir Square in Cairo,as protesters move away from a tear gas canister:
2200 GMT: Tonight's statement from protesters calling for the fall of the Egyptian Government and for a continued sit-in:
2205 GMT: US Secretary of State Hillary Clinton's remarks today....
With respect to Egypt, which, as your question implied, like many countries in the region, has been experiencing demonstrations. We know that they've occurred not only in Cairo but around the country, and we're monitoring that very closely. We support the fundamental right of expression and assembly for all people, and we urge that all parties exercise restraint and refrain from violence. But our assessment is that the Egyptian Government is stable and is looking for ways to respond to the legitimate needs and interests of the Egyptian people.
2118 GMT: Tim Marshall of Britain's Sky TV reports, "Just back from [Tahrir] square. Saw 100 young thugs in plainclothes with truncheons behind police lines. They were with the police."
2115 GMT: A report says 4000 people are coming from Giza to join the crowd in Tahrir Square in Cairo.
2050 GMT: A claim is circulating that 7000 protesters are having a sit-in at Misr Station in Alexandria tonight.
2045 GMT: Ahram Online is reporting clashes tonight between police and protesters in Alexandria (see video in separate entry).
2025 GMT: The website of Egypt's Ministry of Foreign Affairs has been knocked off-line. Earlier today the Minister of Interior website was taken down (see 1610 GMT).
The website of the ruling National Democratic Party also appears to have been limited by attack.
1959 GMT: State TV is reporting one police officer killed in central Cairo.
1955 GMT: Journalist Mohamed Abdelfattah has been detained and beaten. He reported the experience via Twitter.
1953 GMT: Protesters have dispersed from the demonstration outside the Supreme Court. This leaves the mass protest in Tahrir Square as the focus of attention tonight.
1951 GMT: News services are reporting two people killed during protests in the Suez district in northeastern Cairo.
1948 GMT: Ben Wedeman of CNN reports with concern, "Huge number of riot police deploying next to Egyptian museum, troop trucks moving in."
1945 GMT: In Tunisia, there were protests in Gafsa and Sfax, the country's second-largest city, as well as Tunis.
1935 GMT: A participant reports, "All telecommunications down in Tahrir Square. We can't call, update Twitter. I went out to update you and get updates."
1925 GMT: Picture of the Night? Thousands of demonstrators in Tahrir Square in Cairo:
1919 GMT: A round-up of early evening developments in Egypt....
There were continuing clashes, with arrests and injuries, near Parliament and in Tahrir Square as protesters threw rocks and police charged and fired tear gas.
Protesters have maintained their occupation of Tahrir Square as security forces cordon them off. Forces have also put a ring around outside the High Court on Ramses Street.
In Alexandria, police fired tear gas at protesters in Sidi Gaber, Alexandria.
1915 GMT: Returning from an academic break, I find that Al Jazeera is reporting the Egypt Minister of Interior is blaming the Muslim Brotherhood for today's protests.
1700 GMT: Reports escalating of clashes in Tahrir Square in Cairo between police and protesters.
We will be back in two hours, after an academic break, to bring you the latest developments.
1635 GMT: There is a report of a journalist being hit with a rubber bullet in Alexandria.
1630 GMT: Ben Wedeman of CNN writes, "Large groups of plainclothed cops headed to heart of Tahrir [Square]."
1625 GMT: The latest situation in Egypt....
This afternoon, there were clashes and arrests in Sayyeda Zeinab, Shubra, and Tahrir Square in Cairo, with protesters attacking a police armoured vehichle that was firing tear gas canisters. More protests broke out in Mahalla broke out, with factory workers joining in.
The area in front of the Mogamaa Tahrir was described as a "war zone" with protesters throwing rocks at the police, amidst water cannons and tear gas. Protesters toppled and rolled over a police kiosk in Qasr El Aini Street, and clashes continued around the Parliament.
1619 GMT: The New Picture of Day? Tearing down President Mubarak's poster in Mahalla:
1610 GMT: The Anonymous collective has knocked the website of Egypt's Ministry of Interior off-line.
1600 GMT: A fireman in Oum El Bouaghi in eastern Algeria has tried to commit suicide by pouring lighter fuel on himself and setting it on fire. He is in stable condition in hospital.
On 16 January, a civil protection officer attempted self-immolation in the same barracks.
1555 GMT: Lest we forget, given all the excitement in Egypt, there is still a volatile situation in Tunisia....
Hundreds of protesters in Tunisia continued to demonstrate outside Prime Minister Mohamed Ghannouchi's office today, maintaining the pressure to force out Cabinet members linked to the former ruling party RCD.
1550 GMT: CNN's Ben Wedeman writes, "Thousands in tahrir singing national anthem....No police in sight."
1545 GMT: Tim Marshall of Britain's Sky TV in Cairo: "Another 1000 protestors just turned up. It's dusk." Protesters are moving towards Parliament.
One report says 32 people arrested on Qasr-Eini St, 5 in Tahrir Square, 8 in Tera’a Boulaqia in Shubra, 7 in Port Said, 9 in Mansoura.
1530 GMT: A claim from an activist in Cairo: "We are in Tahrir [Square]. At least 7 thousand. Tahrir is ours."
1520 GMT: Back from an academic break to find that Al Jazeera are estimating 20,000 protesters in Alexandria.
There are reports that demonstrators on Cairo's Tahrir (Liberation Avenue) protesters are said to plan on spending the night.
Reports are growing that Egyptian authorities are shutting down Internet services, including Twitter. There is disruption of cell phone service. In a quick test of both claims, Ben Wedeman of CNN reports --- via Twitter --- "Walking toward Parliament. Can't call out."
1350 GMT: Protests are swelling near 26 July Street in downtown Cairo. Police tried to use water cannon; at least has been destroyed by protesters.
1345 GMT: Security forces are moving to protect the Ministry of Interior, as protestors move throughout the city. At least 12 armored vehicles were moving to the area.
Marches are growing in the Shubra section of Cairo.
In Mansoura, demonstrators are marching on State Security Police headquarters. In Giza, thousands are now marching from Dokki to Tahrir Square. Thousands in Ataba are chanting against the interior minister and the president.
1340 GMT: The latest developments in Egypt....
There are now protests have broken out in Aswan. Police have sent in armored vehicles, but there are no clashes yet. In Mansoura, protesters have marched on the town's security directorate building.
Marchers in downtown Cairo have gone through Wekalet El Balah area. Clashes are taking place between protesters and the Central Security Forces near the High Court. Ramses street has been completely shut down by the police.
A protest has started in Meit Uqba, Giza. In Mahalla, a protest march is heading to the Shawn Square. Sinai protesters have shut down the road to the airport used by the Multinational Force Observers.
1250 GMT: Dilemma of the Day --- "My grandmother is out. Don't know whether to hope she joins protests or gets home fast & safe."
1245 GMT: More protest pictures....
And plainsclothes security keeping an eye on proceedings:
1225 GMT: There are now reported demonstrations in Kafr El Sheikh and in the Asafra district of Alexandria (see picture below). Hundreds are reportedly protesting in Mansoura.
At least 25 activists have been detained in Assuit and Tanta, according to the Egyptian Center for Economic and Social Rights.
1219 GMT: To summarise the latest in Egypt....
Most of the news seems to be in Cairo although there was a report of a demonstration in Rafah and heavy security in other cities. In the capital, there seems to be a series of protests rather than a single mass gathering, making it more difficult for the police to exert control.
There are demonstrations in in Mohandessin, in Shubra, and in Bulaq. The major gathering now seems to be in front of the ruling National Democratic Party headquarters on the Nile corniche. Thousands of protesters have taken over the corniche, chanting "Tunis!", and are moving to 15 May bridge.
1215 GMT: A protester gives a flower to a policeman:
1205 GMT: We are now carrying live footage from Cairo.
An observer reports, "Protesters outside ruling party office building in downtown chanting fraud."
This photograph from outside the Opera House:
1140 GMT: The growing protest in central Cairo:
1130 GMT: Ramses Street in Cairo: 
And Tahrir Square:
1125 GMT: Ahram Online says "at least 2000 protesters" heading from 26 July Street to Galaa Street in downtown Cairo. More than 1000 have reached Abdel Moneim Riyadh Square.
The website also confirms Web chatter of the arrest of a number of activists at a Cilantro coffeeshop in Mohandessin, before they headed out for a protest.
1122 GMT: Tim Marshall of Britain's Sky News in Cairo reports, "Several hundred outside supreme court now. Peaceful."
Another observer claims, "Protesters break cordon marching freely down street. Moving towards 26 July [Square]."
1120 GMT: A crowd map of the protests in Egypt is now live.
1105 GMT: More than 100 protesters have started a demonstration in front of the lawyers syndicate in Ramses Street in Cairo.
1100 GMT: An Ahram Online reporter in Alexandria denies earlier reports of protests in Moharram Bek, but says security presence is strong at Rassafa Square.
Police have broken up the Dar el-Salam protest, south of Cairo. No one was detained.
Police have moved against anti-government protesters in Assuit, according to a human rights lawyer Gamal Eid.
Police are searching passengers at the underground metro stations of Matariya, Isaaf, and Tahrir in Cairo. There is a report that Nasser station is closed.
1035 GMT: Reports of a protest in the Maadi section of Cairo, with youth chanting, “With our blood and soul, we sacrifice our country.”
Authorities have set up security cordons at entrances to the city of Mahalla, west of Cairo.
1030 GMT: From a reporter in Cairo: "Within seconds of filming, even with a stills camera, police stop us."
1020 GMT: 12:06 PM Security forces close down the headquarters of the El Ghad Party, headed by Ayman Nour, in Talaat Harb Square in Cairo.
Security forces have set up barriers in the streets adjacent to the press syndicate, lawyers syndicate, and the attorney's building.
Around 300 protesters are demonstrating south of Rafah, chanting against the Emergency Law and calling for the release of detainees.
1015 GMT: A protest has started in Moharram Bek, marching to el-Rasafa Street, in Alexandria.
1010 GMT: Tunisia's government has authorised $355 million for poor rural regions from where protests built against the Ben Ali regime.
Regional Development Minister Ahmed Nejib Chebbi, a former opposition leader, announced the grant on a talk show late on Monday. He said the money would go towards public works projects, reimburse businesses that have suffered damage, and compensate the families of dozens of "martyrs" killed in the protests.
1004 GMT: From Twitter: "A policeman is roaming the halls of the Al Jazeera building in Cairo trying to find out names of people who will cover the Jan. 25 protest."
1000 GMT: There is chatter of "interesting things" happening in Quweisna in the Delta, with workers walking out and residents launching a civil disobedience campaign.
0950 GMT: The latest on the Egyptian situation....
Confirmation that Central Security Forces trucks and police vans are deployed in key locations, including in front of the Supreme Court, and in side streets. Sheikh Rihan Street, where the Ministry of Interior is located, is closed.
There is also a large security presence in Mansoura, with police deploying armored vehicles around the stadium.Police are taking away the IDs of journalists in Mahalla.
First reports have come in of protest, however, with "hundreds" demonstrating in in Dar El Salam, south of Cairo, chanting for "bread and freedom". A protest in front of Cairo University has been cancelled, with faculty instead participating in a demonstration in front of the Supreme Court.
The US and Canadian embassies have asked their citizens in Cairo to avoid expected locations of protests.
0940 GMT: Both Egypt's Muslim Brotherhood and the National Association for Change, headed by Mohamed ElBaradei say that their members have been interrogated and threatened by security forces to prevent them from participating in today's protests.
“A large number of officials in the Brotherhood’s administrative offices in many governorates were summoned by security forces and were threatened with detainment if they participate in the Jan. 25 protests,” said Mohamed El-Beltagy, a prominent Brotherhood member. “Threatening us is completely unacceptable and a useless attempt by security forces. We will continue to advocate the people’s demands until they are implemented by the regime.”
Mustafa Al-Naggar of the National Association for Change asserted, “Security forces verbally attacked our members and interrogated them for hours to obtain any details regarding the protests scheduled for Jan. 25.”
0935 GMT: Picture of Day (so far) in Egypt "They Seem to Be Waiting":
0750 GMT: A useful article in Al Masry Al Youm explains the history of Police Day: it celebrates how Egyptian officers refused to surrender to British military forces in Ismailia on 25 January 1952, More than 40 were killed in the subsequent battle.
It is the headline that is striking, however: "Egypt's Police --- From Liberators to Oppressors".
0745 GMT: First reports from Cairo, "Shobra metro station, Masara, surrounded by CSF [security force] trucks. Police on every street entrance in Garden City, also in front of Parliament." There are also reports of restrictions on mobile phone and Internet service.
Another activist says simply, "Streets are empty. Police are everywhere." One observer counted 33 riot trucks and vans in Tahair Square.
Streets around the Ministry of Interior are closed.
0725 GMT: There continues to be a lot of white noise about social media and activism, so it's refreshing to find a comment that gets to the heart of the matter. Philip Seib writes in "Tunisia, Al Jazeera, and Lessons for Public Diplomacy":
Information is the sustenance of revolution. Whether it is conveyed in a note surreptitiously passed hand to hand or in a broadcast the entire world can watch, evidence of corruption and calls for citizens to rally in the streets pull individuals together, letting them share a reservoir of truth. This is politically intoxicating, and it fuels the collective courage needed to challenge a government.
0710 GMT: We will be watching developments in Egypt, where protesters --- how many? --- will turn out for "a day of revolution" over torture, poverty, and unemployment. Demands include the firing of the Minister of Interior, the cancelling of the perpetual State of Emergency that suspends civil liberties, and a term limit on the Presidency to end the 30-year rule of Hosni Mubarak.
State security officials have said the protests are illegal will be dealt with "strictly".
In Tunisia, continuing protest is intersecting with uncertainty in the Government, including news that the Cabinet will be replaced with a "council of wise men", and the public emergence of the head of the military, General Rachid Ammar, in a dramatic speech to thousands of demonstrators. We have a short video and an an analysis.
In Yemen, President Ali Abdullah Saleh has responded to growing protests by raising salaries for those in the army and by denying claims by opponents that he plans to install his son , who commands the Republican Guard and special forces, as his successor. He told hundred of military officers, in a televised speech, "We are against succession. We are in favor of change ...and these are rude statements, they are the utmost rudeness."
The main opposition groups were unpersuaded. Yesterday, following Saturday's protests of 2500 people in the capital of Sanaa, they announced a campaign to oust Saleh.