(Reuters) - U.S. crude stocks surprisingly plunged more than 12 million barrels last week, data from industry group the American Petroleum Institute showed on Wednesday, boosting the price of oil.

Crude oil storage tanks are seen from above at the Cushing oil hub, in Cushing, Oklahoma, March 24, 2016. REUTERS/Nick Oxford/File Photo

Crude inventories fell 12.1 million barrels in the week to Sept. 2 to 514 million barrels, compared with expectations for an increase of 225,000 barrels.

If Thursday’s report from the U.S. Energy Information Administration shows a similar decline, it would be the largest one-week fall in stocks excluding the U.S. strategic petroleum reserve since April, 1985, according to government data.

The surprise drawdown jolted late-day trading in crude, as U.S. futures jumped sharply to $46.17 a barrel, doubling the day’s gains to nearly 3 percent in after-market trade.

“If it’s accurate, I think it will start to ease fears of oversupply in the market. There’s apprehension of crude restocking as we exit the gasoline season and we exit strong demand,” said Gene McGillian, senior analyst at Tradition Energy in Stamford, Connecticut.

“We’ll just have to wait and see if this is just a one-off or if it’s the start of a trend to pare down those stockpiles.”

Crude stocks have been at record highs in the last two years, thanks in part to the U.S. shale oil boom that boosted U.S. production. That glut has kept crude prices under pressure.

Some analysts said Tropical Storm Hermine, which threatened the Gulf Coast refining region late last week before moving to the U.S. East Coast, may have skewed the figures.

“I think it was rough weather in the waters that prevented a lot of vessels from unloading. Certainly, some production was shut in because of the hurricane,” said Dominick Chirichella, senior partner at Energy Management Institute in New York.

U.S. crude imports fell last week by 1.7 million barrels per day to 7.3 million bpd.

Refinery crude runs rose by 227,000 bpd, API data showed.

Gasoline stocks fell 2.3 million barrels, compared with analysts’ expectations in a Reuters poll for a 171,000-barrel decline.

Distillate stockpiles, which include diesel and heating oil, rose 944,000 barrels, compared with expectations for a 684,000-barrel gain, the API data showed.