Oil futures rose sharply early Friday, trading at their highest since October with support tied to cold weather in the U.S. and elsewhere and supply concerns.

Oil prices rallied more than 4% on Friday to reach their highest levels since October as traders focused on potential supply disruptions from more sanctions on Russia. Brent crude futures gained $3.50,

Oil prices jumped more than 4% on Friday, with global benchmark Brent breaking $80 per barrel for the first time since October on fears that tougher U.S. sanctions on Russia will disrupt crude supplies.

Oil prices fell on Thursday, extending losses from the previous day, pressured by large builds in U.S. fuel inventories last week, though concerns over tighter supplies from OPEC members and Russia capped the decline.

U.S. crude oil inventories fell for a seventh consecutive week, while product stocks saw large builds last week as refineries increased their capacity use.