Massive demonstrations across Egypt have called for an end to Hosni Mubarak's three-decade rule in what observers say is a rare display of popular anger.
Two protesters died in the port city of Suez, east of Cairo, during Tuesday's unrest, and a policeman was also killed when he was hit in the head with a rock in Cairo, an interior ministry official said.
Al Jazeera's Rawya Rageh, reporting from the Egyptian capital on Wednesday, said that more protests were planned, though the streets of Cairo were still reportedly quiet.
Violent clashes between police and protesters lasted into early Wednesday morning, as security services sought to disperse a crowd of thousands that had planned to sleep in Tahrir Square in central Cairo.
"There are no protesters at the Tahrir (Liberation) Square on Wednesday morning after they were dispersed last night ... and traffic at the square is normal," our correspondent said.
"We are hearing from some activists and protesters that there are intentions to take to the streets again, and it remains to be seen whether these calls gain traction."
But the group had said earlier that it would not officially participate in the January 25 protests and denied the accusation.
Multiple waves of protesters filled Tahrir Square on Tuesday - a "day of anger" that had been planned for weeks.
With just eight months to go before a presidential election that could see the ailing Mubarak run for re-election or attempt to hand off power to a successor, protesters in Egypt demanded a solution to the country's grinding poverty and called for "the tyrant" to leave.
"Down with Hosni Mubarak, down with the tyrant," chanted the crowds. "We don't want you!"
Police fired around 50 tear gas canisters, filling Tahrir Square with acrid smoke, Al Jazeera's Adam Makary reported on Tuesday.
Protesters splashed their eyes with vinegar to relieve the sting. Police also fired rubber-coated bullets, striking an Al Jazeera camerman 11 times.
Demands by the protesters were posted on Facebook and passed around Tahrir Square on slips of paper before police moved in.
They included calls for Mubarak and Ahmed Nazif, the Egyptian prime minister, to quit, parliament to be dissolved, and for the formation of a new national unity government following troubled parliamentary elections in November and December.
A union activist repeated the demands to the crowd in the square by megaphone.
More than 80,000 people signed up to protest on a Facebook group set up to organise the event.
Hundreds were injured in the demonstrations, which protesters explicitly linked to Tunisia's popular uprising, which brought down the 23-year government of Zine El Abidine Ben Ali.
Al Jazeera's Rageh said state-run newspapers downplayed the events in their Wednesday editions, but that opposition and independent papers ran comparatively unbiased headlines.
The independent Al-Masry Al-Youm (Egypt Today) newspaper ran a blunt headline: "A Warning."
The interior ministry, which controls the security forces, said authorities wanted to let the protesters express their opinions and accused the crowds of "insisting on provocation."
"Some threw rocks at police ... and others carried out acts of rioting and damage to state institutions," the ministry said in a statement.
The ruling National Democratic Party said some 30,000 protesters had turned out across the country.
"Egyptians have the right to express themselves," Hosam Zaki, a spokesman for the foreign ministry, said.
The protests spread throughout the country to the northern coastal city Alexandria, across the Nile Delta, and east to Suez and Ismailia. Lawyers said dozens were detained.
The US, a close ally of Egypt that has for years given the country the second-largest amount of foreign aid, called for calm.
"The United States supports the fundamental right of expression and assembly for all people," PJ Crowley, the state department spokesman, said in a statement.
"All parties should exercise restraint, and we call on the Egyptian authorities to handle these protests peacefully."
In Washington DC, Hillary Clinton, the secretary of state, said Egypt's government was "stable" and that Egyptians have the right to protest, though she urged all parties to avoid violence.
Discontent with life in Egypt's authoritarian police state has simmered under the surface for years.
"This is the first time I am protesting, but we have been a cowardly nation. We have to finally say no," Ismail Syed, a hotel worker who struggles to live on a salary of $50 a month, told the Associated Press news agency.
Lamia Rayan, 24, said: "We want to see change, just like in Tunisia."
In another parallel with Tunisia, the protests drew energy from the death of a young man: Khaled Said, an Alexandria resident whose family and witnesses say was beaten to death by two policemen in Alexandria last year. Witnesses said Said's name became one of the Tuesday's strongest rallying cries.
Also like the Tunisian protests, the calls to rally in Egypt went out on Facebook and Twitter.
Throughout Tuesday, organisers used Twitter to give minute-by-minute instructions about where to gather in an attempt to outmanoeuvre the police, until the government blocked it in the late afternoon.
Twitter announced that its service had been blocked in Egypt at about 6pm local time on Tuesday (1600 GMT), and said that Twitter and its applications had been affected.
In a message, the company wrote: "We believe that the open exchange of info & views benefits societies & helps governments better connect with their people."
Among the protesters in Cairo was Alaa al-Aswany, author of the best-selling Yacoubian Building, which portrays corrupt politicians, police brutality and terrorism in Egypt.
A keen observer of Egyptian society, al-Aswany said the demonstrations were an important opening for the government's opponents.
"They broke the barrier of fear,'' he said. "The writers of the regime were saying Egypt is not Tunisia and Egyptians are less educated than Tunisians. But here is the thing: these young people proved they can take their rights forcefully."
Nearly half of Egypt's 80 million people live under or just above the poverty line, set by the UN at $2 a day.
The widespread poverty, high unemployment and rising food prices pose a threat to Mubarak's regime at a time when tensions between Muslims and Christians are adding to the nation's woes.
Mubarak, 82, has not appointed a deputy since he became president in 1981 and is widely thought to be grooming his son Gamal to succeed him.
Al Jazeera and agencies