The US says it has temporarily evacuated its staff from the Libyan capital Tripoli over security concerns.
Staff, including marine guards providing security to the embassy, have been transferred to Tunisia "due to the ongoing violence resulting from clashes between Libyan militias," it adds.
Secretary of State John Kerry said there was a "real risk" to staff.
It comes amid fierce clashes between rival militias in the capital, with intense fighting at Tripoli airport.
Libya has been gripped by instability since the 2011 uprising, with swathes of the country controlled by militias.
With no army, Libya's central government has increasingly lost control over the country to rogue and powerful militias in the last two years, says the BBC's Rana Jawad in Tripoli.
Military assistance The US embassy in Tripoli was already operating on limited staffing. All remaining personnel were driven overland to Tunisia in the early hours of Saturday.
The US military said it had "assisted in the relocation" of embassy staff, using F-16 and MV-22 Osprey aircraft.
It said the five-hour operation was "conducted without incident".