Reports say the US ambassador to Libya has died after an attack by militiamen on the U.S consulate in the eastern city of Benghazi.

Ambassador Christopher Stevens is said to be among four U.S officials killed in a protest over an American produced internet film that is said to insult and ridicule the Prophet Muhammad.

The US state department has only confirmed the death of one official - but it has not named them.

Protesters have also attacked the US embassy in Cairo over the film.

The U-S hasn't yet confirmed ambassador Christopher Stevens' death.

The California filmmaker is now in hiding.