Hundreds of Egyptians stormed the building housing Israel's mission in Cairo and threw embassy documents and its national flag from windows, while airport sources said on Saturday that Israel's envoy was set to fly out of the country.
The Interior Ministry said at least 450 protesters were injured during a day of confrontations with police, who used teargas and fired blanks in the air in an effort to disperse them.
Egyptian Prime Minister Essam Sharaf summoned his cabinet crisis team, state media said, while the Interior Ministry put police on alert and cancelled police holidays.
US President Barack Obama called on Egypt to "honor its international obligations" and protect the Israeli mission after protesters, who had been demonstrating at Tahrir Square to push for a timetable for reforms and an end to military trials for civilians, smashed through a wall protecting the embassy building.
Airport sources said the Israeli ambassador Yitzhak Levanon and his family were at Cairo airport early on Saturday, planning to fly out of the country following the assault on the building housing the embassy.
Israel said it had asked the United States for help in guarding the embassy.
Asked about the report that the ambassador and his family were at the airport, an Israeli official in Jerusalem said only: "The ambassador is currently in Cairo."
Activists who spearheaded the uprising that ousted President Hosni Mubarak on Feb. 11 have been piling pressure on the ruling military council to fix a date for parliamentary and presidential elections and to get rid of senior officials who served under Mubarak.
Thousands had converged on Tahrir Square, the epicentre of the pro-democracy protests that toppled Mubarak, after Friday prayers for what was billed as "Correcting the Path" protests.
Some later marched to the opposite bank of the Nile in Giza. Demonstrators used hammers, large iron bars and police barricades to tear down the wall, erected this month by Egyptian authorities after daily protests over the killing of five Egyptian border guards in Sinai.
The five died during an Israeli operation against gunmen who had killed eight Israelis. Egypt threatened to withdraw its ambassador from Tel Aviv. Israel has stopped short of apologising, saying it is still investigating how the Egyptian troops were killed.
Protesters scaled the embassy building, removed the Israeli flag for the second time in less than a month and burned it.
Some also tried to break into the embassy, located in a tower overlooking the Nile, and reached the entrance hall but had not entered inside the mission itself, Israeli and Egyptian officials said.
"The embassy itself has not been breached," an Israeli Foreign Ministry official told Reuters in Jerusalem. An Egyptian security source confirmed that the embassy offices had not been entered.
Witnesses said activists managed to get a hold of some documents belonging to the Israeli embassy and threw them out of the building windows. A group of protesters took down the Israeli flag and hurled it from the building.
The official said the documents thrown from the windows of the tower housing the embassy appeared to be "pamphlets and forms kept at the foyer".
The demonstrators also tried to storm the local police compound, hurled stones at the police and torched at least four vehicles. They also set a public building adjacent to the police compound on fire.
Police responded by firing teargas and blanks into the air, witnesses said.
"This action shows the state of anger and frustration the young Egyptian revolutionaries feel against Israel especially after the recent Israeli attacks on the Egyptian borders that led to the killing of Egyptian soldiers," Egyptian political analyst Nabil Abdel Fattah told Reuters.
Cheers as wall came down
Egyptian police stood aside as activists tore down the concrete wall to the cheers of hundreds of demonstrators, witnesses said..
"It is great that Egyptians say they will do something and actually do it," Egyptian film director and activist Khaled Youssef said, standing among the protesters outside the embassy.
"They said they will demolish the wall and they did ... the military council has to abide by the demands of the Egyptian people," he said.
Friday's demonstrations were organised mostly by secular groups which had been pushing for reforms, a new constitution and an end to the trial of civilians before military courts.
Islamists, including the political party set up by the Muslim Brotherhood -- Egypt's best organised political force after the dissolution of Mubarak's National democratic Party -- have distanced themselves from the planned protests.
The country's military rulers have promised to hand back power to a civilian government after elections, which they said would be held before the end of 2011. The council has also facilitated the trial of Mubarak and several of his aides, including former Interior Minister
Habib al-Adli, on charges of corruption or conspiring to kill some 850 demonstrators.