The dirt road which leads to the front gate of the US mission in Benghazi was sealed off in the morning by defence ministry vehicles mounted with weapons, an AFP correspondent reported.

“About 20 Americans dressed in civilian clothing came and we were asked to protect them until they leave Benghazi,” said a commander of the Libya Shield brigade, a former rebel unit under defence ministry command.

“They arrived in the early morning and worked for three hours collecting evidence,” added the commander, who spoke on condition of anonymity.