U.S. crude futures rose more than $1/bbl on Monday as the threat of supply disruptions from OPEC member Libya grew as unrest in the country intensified, with protesters calling for the departure of veteran ruler Muammar Gaddafi.
The leader of the Al-Zuwayya tribe in eastern-Libya threatened on Sunday to cut oil exports to Western countries within 24-hours unless authorities stopped the "oppression of protesters".
Gaddafi has attempted to put down protests against his four-decade rule, centred on the eastern city of Benghazi.
Libyan security forces have shot dead scores of protesters in the city.
In Bahrain, opposition leaders met on Sunday to discuss demands they will present to the Gulf Arab country's rulers, after scores of protesters returned to the city centre in Manama after four people were killed on Thursday's night-time raid by riot police.
The anti-government demonstrations has raised fears that the unrest could spread to other producer nations in the region.