Britain was on Sunday advising its citizens against travelling to strife-torn Libya and urged all those currently in the country to leave, although its embassy in Tripoli remains open.
"Due to the ongoing and greater intensity of fighting in Tripoli and wider instability throughout Libya, the Foreign and Commonwealth Office (FCO) advise against all travel to Libya," the ministry's website said.
"British nationals in Libya should leave now by commercial means."
The United States evacuated its Libyan embassy staff under air cover Saturday as they faced a "real risk" from fierce fighting around Tripoli airport, Secretary of State John Kerry said.
The airport was closed on July 13 following clashes between armed groups in the area.
Britain's embassy will remain open but with reduced staff, and its ability to provide consular assistance "is very limited", the Foreign Office said.
The ministry warned of a high threat of terrorism, noting that a number of foreign nationals have been shot dead in recent months.
It told those still in Libya to avoid demonstrations or large crowds and to "keep a low profile".
The US announcement that it was evacuating its embassy came hours after the country's interim government warned that the clashes between militia vying for control of the strategic airport were threatening to tear Libya apart.