The US is reportedly considering plans to occupy or blockade Iran’s Kharg Island to pressure Tehran to reopen the strait of Hormuz, despite earlier suggestions by Donald Trump that he was not leaning towards putting “boots on the ground”.

The claims, made on the Axios website, followed previous reporting that the US was considering occupying the key Iranian oil terminal.

The report emerged as Iran’s military threatened it would “hunt down” officials and military commanders from the United States and Israel wherever it could find them in the world.

“We are watching your cowardly officials and commanders, pilots and wicked soldiers,” the armed forces spokesperson Abolfazl Shekarchi said, quoted by state TV. “From now on, based on the information we have on you, the promenades, resorts and tourist and entertainment centres in the world will not be safe.”

Any attempt physically to occupy Kharg Island would probably entail high risks, exposing American forces there to Iranian drone and rocket fire in a geographically confined space.

Just 20 sq km (7.7 sq miles) in size and situated 16 miles (25km) from the Iranian city of Bushehr at the northern end of the Gulf, the Kharg Island terminal exports about 90% of Iranian oil and is supplied by pipes from nearby offshore fields.

Iran is heavily dependent on revenue from fossil fuels, and any attempt to seize such a key strategic asset would almost certainly be resisted.

The Pentagon has deployed the 31st Marine Expeditionary Unit, a rapid-response force of about 2,200 marines, to the Middle East. Military officials have not said what missions the marines being sent to the Middle East would be assigned to carry out.

The Trump administration and its Israeli allies have given contradictory briefings about their intentions in the war. Descriptions of plans appear to change on an almost daily basis, reflected in statements by administration officials grappling with a war whose consequences have spiralled beyond their control.

The war showed no signs of de-escalating on Friday, with an Iranian drone attack hitting a Kuwait refinery and the US and Israel striking 16 Iranian cargo vessels in port towns on the Gulf.

“Following the American-Zionist air attack, at least 16 cargo vessels belonging to citizens of the towns of Bandar Lengeh and Bandar Kong were completely burned in the fire,” a local official from the southern Hormozgan province said, quoted by the Tasnim news agency.

Heavy explosions also shook Dubai as air defences intercepted incoming rockets, as people were observing Eid al-Fitr, the end of the holy Muslim month of Ramadan.

Separately, Israel attacked Syrian government positions, only days after US officials had anonymously suggested using the same Syrian forces to disarm Hezbollah in eastern Lebanon.

As violence continues across the region, from Tel Aviv and Haifa to the Caspian Sea, oil and gas prices are soaring and there are warnings of a spreading global economic shock that has been exacerbated by the increasingly incoherent messaging from Washington.

As a fourth week of war approached, Kuwait said two waves of Iranian drone strikes hit its Mina al-Ahmadi oil refinery, one of three oil refineries in the tiny, oil-rich country on the Gulf. The refinery, which can process about 730,000 barrels of oil a day, was already damaged on Thursday in another Iranian attack.

Iran stepped up its attacks on energy sites in Gulf Arab states after Israel bombed Iran’s massive South Pars offshore natural gas field in the Gulf on Wednesday.

Explosions could be heard in Jerusalem after the Israeli army warned of incoming Iranian missiles.

In a rare statement, Iran’s new supreme leader, Ayatollah Mojtaba Khamenei, who was reportedly wounded in the initial US-Israeli strikes, said Tehran’s enemies needed to have their “security” taken away.

Khamenei has not been seen since he succeeded his father, Ali Khamenei, who was killed in an Israeli airstrike on the first day of the war. His remarks came in a statement issued on his behalf and sent to the president, Masoud Pezeshkian, after Israel killed the intelligence minister, Esmail Khatib, this week.

The renewed attacks followed an intense day during which Iran hit energy infrastructure around the region and launched more than a dozen missile salvoes at Israel after the attack on South Pars.

South Pars, the Iranian part of the world’s largest gasfield, is located offshore in the Gulf and owned jointly with Qatar. With about 80% of power generated in Iran coming from natural gas, the attack posed a direct threat to the country’s electricity supplies.

Late on Thursday, the Israeli prime minister, Benjamin Netanyahu, said the country would hold off on any further attacks on the gasfield at the request of Trump after the Iranian response sent oil prices soaring.

Netanyahu claimed Iran’s capability to produce ballistic missiles had been taken out, but the paramilitary Revolutionary Guards said in comments released on Friday that they were still in production.

“We are producing missiles even during war conditions, which is amazing, and there is no particular problem in stockpiling,” a spokesperson, Gen Ali Mohammad Naini – who was killed in an airstrike on Friday – was quoted as saying in a state-run newspaper.

“These people expect the war to continue until the enemy is completely exhausted,” Naini said. “This war must end when the shadow of war is lifted from the country.”