EL-ARISH, Egypt — U.S. Ambassador to Libya John Christopher Stevens and at least two other embassy staffers were reported killed Tuesday in an assault on the American consulate in the eastern city of Benghazi.

Libyan government officials confirmed to wire services and reporters on the ground  that Stevens and the others were fleeing the consulate when a rocket-propelled grenade struck their vehicle. Al-Jazeera’s correspondent in Benghazi said the bodies of the dead had been taken to the Benghazi airport.

Stevens, a longtime Middle East hand in the State Department, was named ambassador to Libya in May. He had worked in Libya for a number of years, both before and after the fall of slain Libyan leader Moammar Gaddafi. The other dead were not identified in reports by Reuters, CNN, al-Jazeera and others.

Secretary of State Hillary Rodham Clinton confirmed late Tuesday that “one of our State Department officers was killed,” but did not identify the victim. Early Wednesday morning, a senior administration official said information would be released shortly.

“I condemn in the strongest terms the attack on our mission in Benghazi today,” Clinton said in a statement. “As we work to secure our personnel and facilities, we have confirmed that one of our State Department officers was killed. We are heartbroken by this terrible loss. Our thoughts and prayers are with his family and those who have suffered in this attack.”

The violence in Benghazi followed protests in neighboring Egypt, where a group of protesters scaled the wall of the U.S. Embassy in Cairo on Tuesday evening and entered its outer grounds, pulled down an American flag, then tried to burn it outside the embassy walls, according to witnesses.

In both Cairo and Benghazi, protesters said they were demonstrating against a U.S.-released film that insulted the prophet Muhammad.

Clinton said late Tuesday night that she had called Libyan President Mohamed Yusuf al-Magariaf “to coordinate additional support to protect Americans in Libya. President Magariaf expressed his condemnation and condolences and pledged his government’s full cooperation.”

She added that although the United States “deplores” any intentional effort to denigrate the religious beliefs of others, “there is never any justification for violent acts of this kind.”

“We are, obviously, working with Egyptian security to try to restore order at the embassy,” said State Department spokeswoman Victoria Nuland. “We all want to see peaceful protests, which is not what happened outside the U.S. mission, so we’re trying to restore calm now.”

Nuland played down any significance to U.S.-Egyptian relations. “I think the bigger picture is one of the United States supporting Egypt’s democratic transition and the Egyptian government very much welcoming and working with us on the support that we have to offer,” she said.

Referring to the Benghazi incident, Nuland said, “We condemn in strongest terms this attack.”

A Libyan security officer said that in addition to the American killed, at least one other had been wounded. The report by Wanis al-Sharef, an interior minister, could not be immediately confirmed.

In Cairo, relatively few embassy employees were inside when the protesters hopped the wall because many had gone home early, according to a U.S. official speaking on the condition of anonymity because he was not authorized to comment publicly about the developing incident. Later in the evening, the Egyptian military sealed the entrances to the embassy to secure it from the ongoing protest, witnesses reported. Protesters were still outside the Cairo embassy early Wednesday, but Nuland later said that police had cleared the remainder.

A spokesman for the embassy said that Ambassador Anne Patterson was out of Egypt on unrelated business and that all embassy employees were “safe and accounted for.”

The security breach in Cairo appeared to catch both the United States and Egyptian security forces by surprise, even though the protest was announced in advance. Shortly before the protesters went over the wall, witnesses said, few Egyptian police or military officers were nearby.

Local media estimated that about 2,000 people participated in the protest, though in video footage of the incident only about a dozen appeared to have scaled the embassy wall. The protesters on the wall replaced the U.S. flag with a black flag with an inscription that read, “There is no god but God and Muhammad is his prophet.”

A spokesman for Egyptian President Mohamed Morsi did not respond to telephone calls requesting comment. “The security of embassies and providing protection for diplomatic delegates is a responsibility of the utmost priority for official authorities in any country,” the Egyptian foreign ministry said in a statement.

Protests at the U.S. Embassy are a regular feature of life in Cairo, where many people are suspicious of the United States and resent it for its support for Israel. But no previous protests have actually breached the embassy compound.

The embassy is in central Cairo, just a few blocks from Tahrir Square, and is a complex of several buildings surrounded by high white walls. Usually, police check vehicles in the streets surrounding the embassy, and cars must pass through moveable barriers.

The United States also treated the incident with major concern, evaluating the security plans at its own embassy in Cairo.Many protesters at the U.S. Embassy on Tuesday said they were associated with the Salafist political parties al-Nour and al-Asala.

Protesters condemned a video clip that depicted the Prophet Muhammad in a series of humiliating scenes. A controversial Cairo television host, Sheikh Khaled Abdallah, aired clips from the video on an Islamic-focused television station on Saturday, and the same video clips were posted to YouTube on Monday.

Organizers at the embassy protest told the Associated Press that they’d begun planning the protest last week when a controversial Egyptian Christian activist who lives in the United States, Morris Sadek, released a trailer for a movie called “Muhammad.”Depicting the prophet at all is considered deeply offensive by Muslims.

“We are speaking out and will never be tolerant toward any curses for our prophet,” said Moaz Abdel Kareem, 37, who had a long beard typical of followers of the Salafist movement and was carrying a black flag.

Earlier Tuesday, the U.S. Embassy in Egypt had condemned insults to religion, saying in a statement that “we firmly reject the actions by those who abuse the universal right of free speech to hurt the religious beliefs of others.”

A spokesman for the Muslim Brotherhood, of which Morsi is a member, said that the United States should do a better job of protecting Islam.

“It isn’t a matter of freedom of speech,” Muslim Brotherhood spokesman Mahmoud Gozlan said. “It’s a matter of a holy Islamic symbol.”