Donald Trump has threatened to expand US strikes on Iran next week to target power plants and bridges if Tehran does not agree to a deal amid a continuing dispute over the strait of Hormuz.

“Next week it gets really bad for them because next week comes the power plants. Next week comes the bridges,” the US president said in a Fox News interview on Tuesday. “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 made similar comments in March, when he threatened to “obliterate” Iran’s power stations and fresh water plants if Tehran did not agree to peace terms “shortly”. Destroying civilian infrastructure such as power and water facilities would be illegal under international humanitarian law and would probably constitute a war crime.

Trump’s comments came as US forces carried out strikes against Iran for a fourth day straight and reimposed a naval blockade on the country’s ports in the strait of Hormuz.

US Central Command (Centcom) said the latest strikes were aimed at “degrading Iranian capabilities used to attack commercial shipping” in the strait, the key shipping channel for Gulf oil and gas where Tehran has repeatedly carried out attacks on civilian vessels.

Iranian state media reported explosions near the port city of Bandar Abbas, on the Gulf island of Qeshm near the strait of Hormuz, and other locations.

In response, Iran’s Islamic Revolutionary Guard Corps (IRGC) said it had targeted what ⁠it described ⁠as command-and-control, logistics, ​fuel and military equipment facilities belonging to ⁠the US Fifth Fleet in Bahrain.

Both Bahrain and Kuwait came under attack, with Jordan’s army also saying early on Wednesday that its air defences intercepted and shot down three ballistic missiles that entered its airspace.

Iranian State news agency IRNA said earlier that Iranian forces launched a drone attack on a military base in Jordan that hosts American warplanes.

The IRGC warned that if Washington sought to block the region’s oil and gas exports by controlling maritime routes, other export routes serving US and allied interests could also be closed, saying regional energy exports would be “for everyone or ​for ​no one”.

Days of retaliatory strikes across the Middle East by Iran – and both nations’ attempts to vie for control of the waterway through which a fifth of the world’s oil and natural gas passes during peacetime – threaten to push the region back to all-out war.

Trump backtracked from a threat earlier this week that ships would have to pay a 20% fee to the US for “security” in the strait, replacing it with what he described as investment and trade deals with Gulf Arab states.

The US president said he had decided to scrap the toll “based on highly productive conversations with Middle East leadership”, and touted “massive” investments, just five hours before the toll was due to come into effect. He said the US would continue to blockade Iranian ports.

Prospects for negotiations aimed at securing a permanent truce after a fragile interim ceasefire was signed on 17 June appear increasingly dim. Iran’s deputy foreign minister, Kazem Gharibabadi, said the US decision to renew the blockade “has, in a way, dismantled the Islamabad memorandum”.

Asked how long the US strikes would carry on, Trump replied: “They’ll continue until I say it’s enough … 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.”

With Agence France-Presse