There's been a brief outbreak of factional fighting in the Libyan capital, Tripoli.
Members of an eastern faction arrived overnight in an attempt to claim power.
They then left the city after several hours of clashes.
The armed escort had accompanied Fathi Bashagha, who was named as prime minister by a parliament based in eastern Libya.
He has been trying to take over from Abdulhamid al-Dbeibah, who was appointed prime minister after UN-brokered negotiations last year.
Mr Bashagha says his western rival forfeited his claim to office when he failed to hold elections as scheduled.