Oil prices jumped on Wednesday in the wake of Iran's attack on two U.S.-Iraqi bases in retaliation for the killing of its top general, which raised the specter of a spiraling conflict and disrupted crude supplies.

Brent crude futures surged to $71.75 a barrel by more than 5%, the highest since mid-September 2019.

West Texas Intermediate crude futures climbed 82 cents, or 1.3%, to $63.52 a barrel. It earlier reached a high of $65.85, the most since late April last year.

Prices gave up a large part of their gains after the early surges as analysts said market tension could ease as long as oil production facilities remain unaffected by attacks. Tweets by U.S. President Donald Trump and Iran’s foreign minister also appeared to signal a period of calm – for now.

Iran’s missile attack on U.S.-led forces in Iraq came early Wednesday, hours after the funeral of Qassem Soleimani, the commander of the country’s elite Quds Force killed in a U.S. drone strike on Jan. 3.

Tehran fired more than a dozen ballistic missiles from Iranian territory against at least two Iraqi military bases hosting U.S.-led coalition personnel, the U.S. military said Tuesday. Stock, currency and gold markets were also roiled by the attacks.