Brent crude oil rose by more than $1 on Friday as heightened tension in Ukraine ahead of a referendum in the Russian-majority region of Crimea raised worries over Russian oil supplies.
U.S. crude oil rose also, though not by as much. Gains were curbed by large domestic supply builds and lower demand in the U.S. and China, the first and second largest oil consumers.
The closely watched and traded price spread between the American and European crude contracts widened to more than $10 for the second time this week, after 1-1/2 months of tightening, as Brent claims more of the geopolitical risk premium from the Ukraine crisis.
Moscow continued to build up its forces on the Ukrainian peninsula Friday, showing no sign of listening to Western threats of imminent sanctions on Russia if it does not stand down in the worst confrontation since the Cold War. The vote being held on Sunday by pro-Moscow authorities is to determine if Crimea will join Russia.The conflict has underpinned global oil markets as traders worry it could lead to a disruption of oil supplies from Russia, one of the world's biggest oil producers.
Brent crude for April delivery, which expires Friday, was up $1 above $108.48 a barrel, after settling 63 cents lower on Thursday.
U.S. crude settled up 69 cents at $98.98 a barrel after settling 63 cents lower on Thursday.
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