BBC news with Julie Candler.

The American ambassador to Libya Christopher Stevens has been killed in an attack on the US consulate in Benghazi on Tuesday night. Gunmen armed with grenades set the building on fire. A Libyan doctor who treated Mr. Stevens said the ambassador had died from smoke

inhalation

. Three other Americans were also killed. It happened during a protest over a film deemed insulting of the

prophet

Mohammed, but it isn't clear whether the attackers were linked to the protest. Jeremy Bowen reports.

Some reports say that the gunmen who attacked the consular were from a group known as Ansar al-Sharia.Witnesses told reporters, while the attack was going on, the streets surround the consular were

cordoned off

by bearded fighters who looked like jihadists armed with automatic weapons including heavy machine guns and rocket launches.US Secretary of State Hillary Clinton said the killers were part of a small and savage group. In Washington at the White House, President Obama condemned the attack.

Police in Tunis have fired tear gas and rubber bullets to

disperse

a protest about the film. Around 200 protesters try to break into the US embassy in Tunis following several hours of peaceful demonstrations outside.

In Egyptian capital Cairo, angry crowds have again gathered outside the American embassy. From Cairo, here is Jon Leyne.

Security at the embassy has been stepped up, and there is no sign protesters will be able to climb the wall or break into the embassy as they did on Tuesday. President Mursi has been quick to condemn the film. He called for legal action against the film makers in the United States. But Egypt's Muslim Brotherhood-led government has little interest in prolonging the crisis.The government is looking for American help to secure a major IMF loan to