The US military began a renewed round of air strikes on Iran Wednesday evening, sending oil prices surging north after several days of escalating tensions between Washington and Tehran.

Futures on Brent crude (BZ=F), the international benchmark, gained as much as 3.4% to cross above $96 per barrel after falling below the level on Monday. Contracts on US benchmark WTI crude (CL=F) advanced as far as 3.8% to climb above $93 per barrel.

Prices on both contracts pulled back by roughly 1% after Fox News reported comments from President Trump that he spoke with Iranian leaders directly and the US bombing campaign would end shortly after. The US would “bomb the shit out of them” if Iran didn’t sign an agreement put forward by Washington, Fox News reported Trump saying.

The strikes come after threats from President Trump and Secretary of Defense Pete Hegseth throughout Wednesday morning and early afternoon that the US would be resuming more severe action toward Iran after an initial round of strikes on Tuesday.

“We’re going to be attacking them, attacking them very hard,” Trump told reporters at the White House on Wednesday, only hours before the strikes began. “We hit them hard yesterday, and we’re going to hit them hard again today.”

Iran’s top military command said less than two hours after the US airstrikes began that the Strait of Hormuz, the world’s most critical chokepoint for global oil flows, is now completely closed, per Reuters. Iranian media, citing Iran’s Revolutionary Guard, reported that two ships had been struck while trying to make the crossing out of the Persian Gulf.

Seyed Marandi, an advisor to the Iranian negotiating team that met with US negotiators in Vienna, wrote on social media Wednesday that, “Because of the psychopath in the White House, the Strait of Hormuz will now be completely closed.”