Egyptian police made no attempt to intervene during the day as crowds of hundreds tore down an embassy security wall with sledgehammers and their bare hands or after nightfall when about 30 protesters stormed into the Nile-side high-rise building where the embassy is located.

In Jerusalem, an Israeli official confirmed the embassy had been broken into, saying it appeared the group reached a waiting room on the lower floor. He spoke on condition of anonymity because he was not permitted to release the information.

Israel’s ambassador, Yitzhak Levanon, his family and other embassy staff rushed to Cairo airport and left on a military plane for Israel, said airport officials who spoke on condition of anonymity because they were not authorized to speak to the media.

Israeli officials refused to comment on the ambassador’s departure. No one answered the phone at the embassy late Friday.

Since the fall of Mubarak — who worked closely with the Israelis — in February, ties have steadily worsened between the two countries. Anger increased last month after Israeli forces responding to a cross-border militant attack mistakenly killed five Egyptian police officers near the border. Egypt nearly withdrew its ambassador from Israel, and protesters demanded the expulsion of the Israeli ambassador.

Calls have grown in Egypt for ending the historic 1979 peace treaty with Israel, a pact that has never had the support of ordinary Egyptians.

Several large protests have taken place outside the embassy in recent months without serious incident.

On Friday, Egyptians held their first significant demonstrations in a month against the country’s military rulers, with thousands gathering in Cairo and other cities. Alongside those gatherings, a crowd massed outside the Israeli Embassy’s building.

It quickly escalated with crowds pummeling the graffiti-covered security wall with sledgehammers and tearing away large sections of the cement and metal barrier, which was recently put up by Egyptian authorities to better protect the site from protests.

For the second time in less than a month, protesters were able to get to the top of the building and pull down the Israeli flag. They replaced it with the Egyptian flag.

Crowds outside the building photographed documents that drifted to the ground and posted some of them online.

Mustafa Sayid said he was among the group of protesters who broke into the embassy. He showed a reporter cell phone video footage he said he recorded inside of young men ransacking the room.

The group got into the building through a third-floor window and climbed the stairs to the embassy. They worked for hours to break through three doors to enter the embassy, said the 28-year-old man. They encountered three Israelis and beat one of them.

Several Egyptian military policemen appeared and escorted the Israelis to safety but did not attempt to arrest any of the protesters, who then set about dumping files out the windows, he said.

“They have papers on us, they collect information on us, so it’s only fair that we share information on them,” he said.

It was not until several hours later that Egyptian police and military forces firing tear gas moved in to try to disperse the protesters from around the embassy. By that time, the crowds of youths had swelled to several thousand. Protesters were cleared from inside the building but held their ground outside, lobbing firebombs at the forces and setting fire to several police vehicles.

The military moved about 20 tanks and troop transport trucks into the area. State radio reported that one person died of a heart attack. About 450 people were injured, including 200 who had to be hospitalized, the Health Ministry said.

In Washington, President Barack Obama assured Israeli Prime Minister Benjamin Netanyahu that the U.S. was acting “at all levels” to resolve the situation.

Obama expressed “great concern” about the situation, the White House said.

Senior Israeli officials were holding discussions on the embassy breach. Israeli Defense Minster Ehud Barak said in a statement that he also spoke with his American counterpart, Leon Panetta, and appealed to him to do what he could to protect the embassy.

The demonstrations against Israel coincide with increasing discontent among Egyptians with the Supreme Council of the Armed Forces, which took control of the country when Mubarak was forced out on Feb. 11 after nearly three decades in power.

Several thousand massed Friday in Cairo’s Tahrir Square, as well as in the cities of Alexandria, Suez and elsewhere. Demonstrators in Cairo also converged on the state TV building, a central courthouse and the Interior Ministry, a hated symbol of abuses by police and security forces under Mubarak. Protesters covered one of the ministry’s gates with graffiti and tore off parts of the large ministry seal.

Seven months after the popular uprising that drove Mubarak from power, Egyptians are still pressing for a list of changes, including more transparent trials of former regime figures accused of corruption and a clear timetable for parliamentary elections.

Activists accuse the council, headed by Mubarak’s defense minister, Field Marshall Hussein Tantawi, of remaining too close to Mubarak’s regime and practicing similarly repressive policies, including abusing detainees. The trials of thousands of civilians in military courts has also angered activists.

“In the beginning we were with the military because they claimed to be protectors of the revolution, but month after month nothing has changed,” said doctor Ghada Nimr, one of those who gathered in Tahrir Square.

One banner in Cairo read, “Egyptians, come out of your homes, Tantawi is Mubarak.”