Oil rebounded on Tuesday from the previous session's tumble, lifted by fighting that threatened Libya's oilfields.
U.S. crude futures, also known as West Texas Intermediate or WTI, closed up 1.88 percent, at $50.52 a barrel. Meanwhile, front-month Brent crude futures were trading up $1.20 at $61 a barrel, having rallied more than $2 at one point.
Higher prices imposed by Saudi Arabia for its crude buyers in Asia, the U.S. and northwest Europe did not immediately boost benchmark Brent and U.S. oil futures, although some traders saw the move as supportive.
Brent jumped almost 3 percent, trading firmly above the $60-a-barrel support level, as rival Libyan forces carried out tit-for-tat air strikes on oil terminals and an airport, reviving fears over supplies from the OPEC member.
Brent had tumbled nearly 5 percent on Monday, its biggest loss in a month, on speculation that a quick nuclear deal between Iran and the West could ramp up Tehran oil exports that would add to global inventories.