Residents check their cellphones as they sit at a cafe overlooking commercial vessels anchored in the Strait of Hormuz, off Bandar Abbas, Iran, Sunday. (Razieh Poudat/ISNA via AP)

DUBAI, United Arab Emirates (AP) — The U.S. announced a new round of strikes on Iran on Monday, hours after President Donald Trump said Washington is “reinstating” a blockade on Iran in the Strait of Hormuz and, in a seeming policy reversal, will charge other ships for safe passage.

All of that comes as Iran has insisted it actually controls the critical waterway, and as the new exchange of fire threatened a return to all-out war.

U.S. Central Command announced on social media that the U.S. military had begun another round of strikes against Iran.

“These strikes will continue imposing a heavy cost on Iranian forces and degrade their ability to attack innocent civilians and commercial shipping in the Strait of Hormuz,” the U.S. military said.

The new round of attacks followed Trump telling conservative radio host Hugh Hewitt, “We’re going to hit them very hard tonight and we’re going to hit them hard tomorrow — and there’s not a damn thing they can do about it.”

“They have nothing,” Trump added. “They have nothing going, other than they have big mouths.”

They followed the U.S. changing a policy that, until now, said the strait should remain open to all without tolls — as it was before the U.S. and Israel attacked Iran on Feb. 28. Any attempt by the U.S. or Iran to charge fees would violate global norms on freedom of navigation and raise tensions, likely causing further economic disruption far beyond the region.

The price for a barrel of Brent crude oil, the international standard, rose 7.8% to $81.92 a barrel on Monday, still well below the nearly $120 reached at the height of the war.

Trump also told Hewitt that the agreement reached last month was “built to test” Iran, adding that “when you’re dealing with sleazebags don’t mean much.”

Trump said he questioned why the U.S. was entering into a deal to create a ceasefire with Iran rather than moving toward a full deal first. Trump last week declared the ceasefire was “over.”

“They didn’t honor the test,” the president said.

Exchanges of fire in recent days, sparked by Iranian attacks on ships, had already cast further doubt on the interim peace deal. Washington had lifted a blockade it imposed in mid-April as part of that deal, which also called for the strait to be fully reopened.

“We are reinstating the THE IRANIAN BLOCKADE,” Trump said on social media. “All other countries will have fair and open use of the Strait.”

The president said the U.S. would be “reimbursed” by 20% of the value of cargo to help cover “any and all costs necessary to do the job of providing safety and security.”

Iran asserts it has the right to manage traffic through the strait and potentially charge fees in accordance with the interim peace deal. The U.S. has disputed that.

Iran on Monday vowed to fight back against any U.S. interference in the strait. Iran’s Foreign Minister Abbas Araghchi mocked Trump on social media and used his support for tolls to legitimize Iran’s position.

“POTUS is absolutely right. Whoever provides secure and safe passage of commercial vessels through the Strait of Hormuz should be compensated for this service,” Araghchi wrote on X. “Iran has always been the GUARDIAN of the Strait and will remain so FOREVER. 20% is of course too much. We will be fair.”

The International Maritime Organization, the United Nations agency overseeing international shipping, said it was waiting to find out more about Trump’s proposal but remained opposed to tolls for passage through international waterways.

“There is no legal basis through which to introduce mandatory tolls simply to transit through a strait,” it said in a statement.