As clashes continued late into the night, Egypt's State television asked protesters to leave Tahrir Square. Egyptian security stormed rooms at a hotel nearby, according to one reporter, and took down cameras and feeding equipment from its balconies.
Fiery Molotov cocktails -- gasoline bombs -- could be seen thrown into the crowd, although it was not clear which side was launching them. Water cannons were also fired at protesters. There were multiple reports of petrol bombs causing fires inside the grounds of the Egyptian Museum.
The White House condemned the riots but stopped short of condemning the government for the violence. President Obama "found the images outrageous and deplorable," White House Press Secreatry Robert Gibbs said.
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Each road going into Tahrir Square seemed to have its own drama unfolding. A human chain of anti-government protesters was seen on one side trying to block pro-government supporters from entering. On the next road, a thick mob pushed into what appeared to be street fighting.
The two sides skirmished with fists, rocks and bottles as helicopters flew overhead. Riders were pulled from camels and horses, and injured demonstrators, many with bloodied faces, were carried away. Warning gunshots were fired and tanks were placed to keep the two sides separated, but neither move by the army had any effect.
Protesters earlier were seen rushing towards pro-Mubarak supporters to push them out of Tahrir Square, which has in recent days, become a symbol of liberation for protesters. From ABC News' vantage point on a roof of a building in Tahrir Square, the military was blocking about 2,000 pro-Mubarak protesters from entering.
Death Toll in Egyptian Uprising Put at Three
Egypt's health minister said that three people died in the chaos and as many as 600 were injured, but anti-government activists said those numbers were low.
Thousands of pro-Mubarak demonstrators converged on the city's center earlier today and clashed with the anti-Mubarak protesters who have occupied the city's main square for more than a week, demanding the president step down immediately. Pro-Mubarak demonstrators also lashed out at the foreign press, particularly Al Jazeera, who they blame for stirring the uprising.
An angry mob surrounded and chased the ABC News crew in a car today, shouting that they hate America. They kicked in the car doors and broke the windshield as we drove away.
Mubarak's supporters came out a day after the 82-year-old president announced that he will not run for reelection, but insisted that he would stay in office until elections are held in September.
The mood in Tahrir Square turned from jubilation on Tuesday to tension today, as demonstrators were sprayed with tear gas.
Initially nervous over the appearance of thousands of chanting pro-Mubarak supporters, including some riders with whips, they quickly fought back, pulling riders off their mounts and attacking them.
They also formed a human chain, in more of a symbol than a show of force because of the sheer number of pro-Mubarak demonstrators.
Television showed the two sides separated by trucks, but pelting each other with bottles and stones.
Opposition protesters charged that those supporting the president were Mubarak's thugs, paid by the administration to disrupt their largely peaceful gathering. But the Ministry of Interior denied that was the case and that security forces were among protesters in Tahrir Square.
Police were absent once again today, though officers in civilian clothes were seen roaming the crowds. The army, deployed to secure peace, stood mainly on the sidelines.
Internet was restored today and the government eased curfew hours, but that has had little impact on the demonstrations in the heart of Cairo. The number of protesters in Tahrir Square was considerably less than Tuesday, which marked the largest day of gathering in the protests that started last week.
Mubarak announced late Tuesday that he would finish his term, but not seek re-election in the September elections, but that did little to appease protesters, who are demanding his immediate removal.
Muhammed ElBaradei, the Nobel laureate who has emerged as a de facto opposition leader, dismissed Mubarak's move as a "trick" to stay in power.
"What is happening now is the continuance of a regime that knows that their people don't want them in power," ElBaradei told Al Jazeera. "What is happening now is security forces are attacking the Egyptian protesters. This was proven when we found that they had changed their clothes on side roads before coming in."
Mubarak's announcement has left many people conflicted about the state of the country. Some, who want to see him removed immediately, say his promises of stepping down and a speedy election are not enough.
"This is a very bad feeling. We feel deceived," one teary-eyed woman told ABC News.
Others say they are nervous about Egypt's future in Mubarak's absence.
"They are looking for the stability of the country. Maybe if he left, and one day the country will fall," another woman told ABC News.
Egypt Clashes Escalate Despite Mubarak's Speech
Mubarak's announcement Tuesday that he will stay through his term did little to quell protesters calling for his immediate removal.
"My first responsibility is to restore the security and stability of the homeland, to achieve a peaceful transition of power in a way that will protect Egypt and Egyptians, and that will allow for responsibility to be given to whomever the people elect in the forthcoming elections," Mubarak said in his second speech to the nation since the protests began a week ago.
A stoic Mubarak announced that he will ask the new government to speed up elections, which are scheduled to be held in September. He vowed to honor people's demands, to protect the citizens honestly and end corruption.
Striking a patriotic tone and emphasizing his military background, the 82-year-old president, who has held on to power for 30 years, defended his own record and suggested he will die on Egyptian soil even when he steps down.
"I never wanted power or prestige, and people know the difficult circumstances in which I shouldered responsibility. ... I have spent enough time preserving Egypt," Mubarak said. "History will judge me."
President Obama hailed Mubarak's decision but also urged that the transition to a new government "must begin now."
"An orderly transition must be meaningful," Obama said in remarks made after Mubarak's speech. "It must be peaceful and it must begin now."
Obama also praised the peaceful demonstrators in Egypt, calling them an "inspiration to people around the world."
"To the people of Egypt, particularly the young people of Egypt, I want to be clear," Obama said. "We hear your voices."
The situation in Egypt is particularly alarming to the United States. Egypt is one of United States' closest allies in the Middle East. It is only one of two Arab countries that recognizes Israel and has helped broker key peace deals. Mubarak's government has also been a close U.S. ally in the fight against terrorism. Egypt is also home to the Suez Canal, and any instability in the region could be gravely dangerous to U.S. interests in the region.
Just hours after Mubarak's speech, Al Jazeera was reporting there were shots fired in Alexandria during violent clashes between pro-Mubarak and anti-government demonstrators.
Yemen's president Ali Abdullah Saleh vowed not to run for re-election in 2013 and also said his son will not seek the presidency. Protests have spurred up in that country in recent weeks, raising concern that the uprising in Egypt and Tunisia could force the government out in Yemen, another U.S. ally.
Jordan's King Abdullah sacked his government Tuesday amid protests that were directed mainly at prime minister Samir Rifai.
After Egypt, Jordan is United States' second biggest ally in the region and only the second Arab country to recognize Israel.
The cabinet of the Palestinian Authority in the West Bank also said it will hold municipal elections "as soon as possible." And in Gaza, which is run by the Islamic group Hamas, demonstrators sympathetic to the Egyptian cause were arrested, according to the Associated Press.
The U.S. government continued to pull its citizens out of Egypt as protests gain momentum. The U.S. Embassy said today it expects to evacuate more than 1,000 Americans over the next two days on special chartered flights. The State Department issued a mandatory evacuation order Tuesday calling for all non-essential U.S. embassy staff to leave.
ABC News' Nasser Atta, Lama Hassan and Alexander Marquardt contributed to this report.