LONDON -- Oil company BP ( BP) says it is temporarily withdrawing some nonessential and non-Libyan staff from its office in Libya's capital following similar action by Britain's Foreign Office.David Nicholas, a BP spokesman, said the move is "a precautionary measure" on advice from the Foreign Office. He wouldn't say how many staff will be affected but stressed that the Tripoli office remains open. The U.K. Foreign Office said Friday it was temporarily withdrawing some staff from its embassy in Tripoli in light of recent political unrest. Militias have stormed and surrounded government buildings in Tripoli in recent weeks, and rallies to protest the armed groups have ended in violence. BP has a limited presence in Libya, where it has long-term exploration contracts but is not currently engaged in any operations.