• Brent futures set for longest run of weekly gains since July

• Lower Russian exports and cold weather also supporting market

Oil jumped to its highest in three months as traders digested a report that Indian oil refiners are bracing for new US sanctions that would hit flows from Russia.

Brent futures rose 4.3% as high as $80.23 a barrel. The tougher measures would target more than 180 tankers carrying Russian oil, as well as maritime insurance providers based in the country, Reuters said, citing Indian refining sources it didn’t identify.

Oil stocks rose. Chevron up 2.2%; Occidental up 2%; Exxon Mobil up 1.6%.

The potential for sanctions on Russia was already on the market’s radar, but the scope was unclear. The targeting of such a big number of tankers could restrict how many vessels Russia has access to.

“Additional sanctions against the Russian oil and insurance industry has added further fuel to the fire, as it raises the prospect for lower supply during a period of strong winter-related demand,” said Ole Hansen, head of commodities strategy at Saxo Bank.

The market has also been supported by dwindling US crude stockpiles, lower seaborne exports from Russia and cold weather.

Brent’s prompt spread — the price difference between its two nearest contracts — widened to as much as 99 cents a barrel in backwardation, a bullish pattern. A month ago, the spread stood at just 29 cents.