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, the US State Department said.

The evacuation came only hours after the Libyan government warned the country could be torn apart by clashes between rival militias for control of Tripoli airport.

US Secretary of State John Kerry, speaking during a visit to Paris, said there had been a "real risk" to personnel and insisted that the US was "suspending" operations, but not closing the embassy in the Libyan capital.

"Due to the ongoing violence resulting from clashes between Libyan militias in the immediate vicinity of the US embassy in Tripoli, we have temporarily relocated all of our personnel out of Libya," deputy State Department spokeswoman Marie Harf said in a statement.

Pentagon spokesman Rear Admiral John Kirby said the "embassy staff was driven in vehicles to Tunisia" in a five-hour operation.

The Marine security guards based at the embassy were also evacuated and guarded the convoy, but US officials would not confirm how many people had been pulled out for security reasons, and gave only a few operational details.

The State Department also issued an updated travel warning cautioning Americans against travelling to Libya, and urging all those in the country to "depart immediately."

Libya has been gripped by instability since the 2011 uprising, with swathes of the country controlled by militias.

RA/SHI