US President Donald Trump has refused to rule out a ground campaign in Iran, claiming that unspecified allied forces could seize key strategic sites like Kharg Island without the involvement of American troops, while threatening to expand the bombing campaign to include power plants and bridges.

In an interview with Fox News on Tuesday, Trump said he would consider a ground operation “if I thought it was appropriate.”

“Sometimes you need a ground campaign, but we have other people who will do the ground campaign for us... But we have already hit Kharg Island twice, even three times. I said, ‘Hit everything but the oil!’” Trump said.

Located about 25km (15 miles) off Iran’s Gulf coast, Kharg Island handles roughly 90% of the country’s crude exports and serves as the primary outlet for its oil revenues.

Ahead of the now-broken April ceasefire, Trump had already threatened to seize Kharg Island “to take the oil.” Asked directly whether he still intended to seize the island, Trump replied: “As far as taking it is concerned, if we degrade them far enough and deep enough, I would do that.”

The president also vowed to intensify the air campaign, saying US strikes would continue until he personally decided “it’s enough.”

“They’ll continue until I say it’s enough. Next week comes the power plants. Next week comes the bridges. We’re going to knock out all their power plants. We’re going to knock out all their bridges, unless they get to the table and negotiate,” Trump said.

Trump further warned that Iran “won’t have anybody left” unless it reached a deal with Washington, claiming US officials had relayed that message to Tehran during contacts held “about an hour ago.”

“We’re being very careful with the civilian population,” said Trump, who has repeatedly threatened to bomb Iran into oblivion, once warning that “a whole civilization will die” if Tehran failed to comply with US and Israeli demands.

More than 1,500 civilians have been killed in Iran since the US-Israeli bombing campaign began on February 28, according to local authorities. One of the deadliest incidents was the strike on the Shajareh Tayyebeh girls’ elementary school in Minab, which killed 168 people, mostly children. Open-source investigations by multiple media outlets have concluded that the school was likely hit during a US strike on a nearby IRGC naval base. Trump repeatedly denied American responsibility but said last month that “mistakes are made” and “nobody did that on purpose.”