Over 200 were injured in Cairo on Thursday in the city's worst violence in months, as Egyptian police engaged in street battles with protesters near the US embassy, DPA reported.
Security forces, deployed across the area near Tahrir Square, fired tear gas against stone-throwing demonstrators apparently infuriated by a US-made film attacking Islam.
State television, quoting the health ministry, reported 224 people were injured in the fighting, the worst clashes since Mohammed Morsi became Egypt's first Islamist president in June.
The interior ministry said 31 security personnel also were injured, as state television reported that the minister inspected the area and urged police to act with restraint.
The demonstrators set two police vans on fire and blocked a road leading to the embassy, according to state television. Twenty-three people were arrested on suspicion of committing acts of violence, the broadcaster reported.
Security forces set up barbed wire barricades around the embassy to prevent the protesters from reaching it, while trucks full of riot police periodically headed towards the area from other parts of the city.
Protesters were still thronging the area past midnight on Thursday as Islamists planned a "million-man" protest demonstration to take place after Friday prayers.
The demonstrators are demanding an official US apology over the video, which has also sparked outrage in other Muslim countries.
President Morsi, currently on an inaugural trip to Europe, condemned the anti-Islam video, but called on Egyptians not to attack diplomatic missions.
"These acts are unacceptable and we count on the US administration and the US people to take serious steps in order to put an end to that because it is considered a crime against humanity and a crime against Muslims," he told a press conference in Brussels.
"It is our duty to protect the visitors and the guests of Egypt because this is a human duty, a political diplomatic and also an Islamic duty to protect our visitors and guests," he added.
Egypt's main Salafist party, the Nour party, also condemned the violence.
"We appreciate the feelings of anger of millions of Muslims at the attack on the standing of the Prophet, but we emphasize the need to keep to peaceful methods and avoid resorting to violence," the party said in a statement on its official Facebook page.
The party also asked protestors to stay away from diplomatic missions.
The violence comes two days after the US ambassador to neighbouring Libya, and three other Americans, were killed in an attack by insurgents apparently provoked by the film.
US President Barack Obama called on the leaders of Libya and Egypt to ensure the safety of US diplomatic facilities and personnel, the White House said Thursday.
Obama "underscored the importance of Egypt following through on its commitment to cooperate with the United States in securing US diplomatic facilities and personnel," the White House statement said.
Meanwhile, Egypt's chief prosecutor, Abdul-Maguid Mahmoud, has placed US pastor Terry Jones and 10 Coptic Christians in the US on a watch list at the country's border checkpoints in connection with their reported involvement in producing the "blasphemous" video, state media reported Thursday.
Jones, the obscure leader of a small church in Florida, has periodically provoked outrage in the Muslim world by burning or threatening to burn the Koran.
On Tuesday, the anniversary of the September 11, 2001, attacks on the US, Jones praised the video, Innocence of Muslims, which he said showed "the destructive ideology of Islam."