French, Spanish, and British ambassadors are in Tripoli in support of the new U.N.-mediated Libyan government.
It is the ambassadors' first visit to the Libyan capital in two years, after most embassies closed in 2014 due to fighting between rival militias. Libya later became engulfed in war that split it between two rival governments and parliaments.
The diplomats will meet with deputies of new Prime Minister Fayez Serraj.
Italian Foreign Minister Paolo Gentiloni visited Tripoli last week and announced plans to reopen embassies.
Italy, France, and other Western nations are increasingly concerned about a powerful Islamic State force in Libya that controls the city of Sirte and has perpetrated attacks across the country. These nations have offered to train security forces in Libya to fight this growing threat.
Libya has been in a state of chaos since leader Moammar Gadhafi was toppled and killed in 2011.