By Anna Hirtenstein

LONDON (Reuters) -Oil prices surged on Friday and were on track for a third straight week of gains as traders focused on potential supply disruptions from more sanctions on Russia and Iran.

futures gained $2.66, or 3.5%, to $79.58 a barrel by 1154 GMT, reaching their highest in more than three months. U.S. West Texas Intermediate crude futures advanced $2.64, or 3.6%, to $76.56.

Over the three weeks to Jan. 10, Brent has climbed 9% while WTI has jumped 10%.

“There are several drivers today. Longer term, the market is focused on the prospect for additional sanctions,” said Ole Hansen, head of commodity strategy at Saxo Bank. “Short term, the weather is very cold across the U.S., driving up demand for fuels.”

Ahead of U.S. President-elect Donald Trump’s inauguration on Jan. 20, expectations are mounting over potential supply disruptions from tighter sanctions against Iran and Russia while oil stockpiles remain low.

This could materialise even earlier, with U.S. President Joe Biden expected to announce new sanctions targeting Russia’s economy before Trump takes office. A key target of sanctions so far has been Russia’s oil and shipping industry.

“That would be the farewell gift of the Biden administration,” said PVM analyst Tamas Varga. Existing and possible further sanctions, as well as market expectations of draws on fuel inventories because of the cold weather, are driving prices higher, he added.

The U.S. weather bureau expects central and eastern parts of the country to experience below-average temperatures. Many regions in Europe have also been hit by extreme cold and are likely to continue to experience a colder than usual start to the year, which JPMorgan analysts expect to boost demand.

“We anticipate a significant year-over-year increase in global oil demand of 1.6 million barrels a day in the first quarter of 2025, primarily boosted by … demand for , kerosene and LPG,” they said in a note on Friday.

Meanwhile, the premium on the front-month Brent contract over the six-month contract reached its widest since August this week, potentially indicating supply tightness at a time of rising demand.

Inflation worries are also delivering a boost to prices, said Saxo Bank’s Hansen. Investors are growing concerned about Trump’s planned tariffs, which could drive inflation higher. A popular trade to hedge against rising consumer prices is through buying oil futures.

Oil prices have rallied despite the U.S. dollar strengthening for six straight weeks, making crude oil more expensive outside the United States.