Oil prices are rising after the U.S. administration raised doubts about the temporary truce in the war with Iran.

The U.S. administration said the agreement to pause fighting was “over,” adding that it would allow negotiations to continue.

The price for a barrel of Brent crude climbed 5.3% to US$78.12 after briefly topping $79 in the morning. That’s still well below its peak from earlier in the war, when the price for the most actively traded contract reached nearly $120. But the jump is unsettling because oil prices had just dropped back to where they were before the war.

The worry is that a continuation of the war will block the Strait of Hormuz and keep oil tankers bottled up in the Persian Gulf instead of delivering crude to customers worldwide.

Oil prices climbed immediately after Trump said, “For me, I think it’s over” about the status of the ceasefire. He added that U.S. representatives can continue negotiations, but he cast doubt on the outcome. “They can talk, but I think they’re wasting their time,” he said.

Trump later said the United States was preparing for another night of strikes against Iran.

On Wall Street, companies with big fuel bills fell to some of the biggest losses. United Airlines lost 3.4%, and Norwegian Cruise Line Holdings fell 2.1%.