Why does the US have Iran's Kharg Island in its sights?

US President Donald Trump recently vowed to take Kharg Island - a major oil terminal off the coast of Iran - in the "not too distant future".

In a Truth Social post on Thursday morning, Trump escalated his rhetoric against Iran, saying the US soon would be "taking Kharg Island, and other oil infrastructure points, and assume total control of their Oil and Gas Markets" and it would be striking Iran hard that night.

But later on Thursday, while appearing on Fox News, Trump seemed to soften his stance on the crucial spot for transporting Iranian crude oil, saying instead that his "preference" had always been "to take Kharg Island" which he said could make a "fortune" for the US. He added that he doubted the American people had "the stomach for it", adding that he "does not want to have to put boots on the ground".

Soon after, he posted on social media that he was cancelling the air strikes as well, citing progress in negotiations with Tehran.

But the island could still be in US sights. Two months ago, after Iran and the US started the war with Iran, Trump first said he wanted to "take" the oil and was considering seizing Kharg Island.

On 13 March, the US launched airstrikes on the rocky outcrop, with Trump saying US forces had "totally obliterated" every military target there. But it held off targeting the island's oil infrastructure.

There has been speculation for some time about whether US forces will at some point attempt to take over Kharg Island.

In an interview with the Financial Times in March, Trump said he wanted to seize it, but noted an operation "would mean we had to be there for a while".

Trump said at the time: "Maybe we take Kharg Island, maybe we don't. We have a lot of options."

He added: "It would also mean we had to be there [in Kharg Island] for a while... I don't think they have any defence. We could take it very easily."

Sources told the BBC's US partner CBS News that Pentagon officials have made detailed preparations to deploy ground forces into Iran.

Both the Pentagon and the White House have declined to comment onspecific troop deployments or potential plans - but have repeatedly made clear that the option is available.

Taking the island would effectively cut off the Islamic Revolutionary Guard Corps (IRGC)'s economic lifeline, affecting its ability to conduct the war, security analyst Mikey Kay, from the BBC's Security Brief, says.

It could choke off Iran's oil exports and provide a platform for the US military to carry out attacks against the mainland.

The US could also use the island as leverage to compel the Iranians to keep the strait open.

But any US operation to seize the island would be challenging, according to Aaron Maclean, host of the School of War podcast and a CBS News national security analyst.

A US landing force would have to move considerable distances, either through naval vessels or as part of an airborne landing force.

Iran's parliament speaker, Mohammad Bagher Ghalibaf, previously warned that his country's forces were "waiting for American soldiers" and they would "rain fire" on any US troops attempting to enter Iranian territory.

An Iranian military official previously toldlocal media that shipping in the Red Sea would be targeted in the event of a ground invasion.

Iran has reinforced its defences on Kharg Island in recent monthsin response to the threat, including deploying additional military personnel and air defences, sources told CNN.

Tehran has sent additional shoulder-fired, surface-to-air missiles to the island and has laid traps, including anti-personnel and anti-armour mines in the waters surrounding it, the website reported, citing "multiple people familiar with US intelligence".

Kharg Island is a small rocky outcrop just 15 nautical miles (24km) off the coast of Iran.

Ninety percent of Iran's crude oil comes through a terminal on the island - transported through pipes from the mainland.

Trump has specifically mentioned the potential for targeting these pipelines, but said he had so far held off to avoid long-term damage to Iran's economy.

"We can do that on five minutes' notice. It'll be over," Trump said on 16 March. "Just one simple word, and the pipes will be gone too. But it'll take a long time to rebuild that."

Very large tankers - capable of carrying up to 2 million barrels of crude oil - around 85m gallons - are able to come up to the island's long jetties to pick up the oil. The island's coast is close enough to deep waters, unlike the shallower coast of the mainland.

The tankers then come back down the Gulf and out of the Strait of Hormuz, to China - the main buyer of Iranian oil.

The island provides a major source of revenue for the IRGC.

Trump said on 13 March that the US Central Command (Centcom) had executed "one of the most powerful bombing raids in the History of the Middle East and totally obliterated every MILITARY target in Iran's crown jewel, Kharg Island".

He added that "for reasons of decency" he had "chosen NOT to wipe out the Oil Infrastructure on the Island".

Centcom said US forces had struck more than 90 Iranian military targets on the island, "while preserving the oil infrastructure".

The regional military command unit said it had destroyed naval mine storage facilities, missile storage bunkers and numerous other military sites.

Iranian state media reported that no damage was done to the island's oil facilities. The semi-official Fars news agency said US attacks targeted air defences, a naval base, an airport control tower and a helicopter hangar.

Following the US attack, Ehsan Jahanian, political deputy to the governor of Bushehr province in southern Iran, said oil was continuing to be exported, according to a report by the IRGC-affiliated Tasnim news agency.

The country's military warned that oil and energy infrastructure belonging to firms working with the US would "immediately be destroyed and turned into a pile of ashes" if its energy facilities were attacked.

Then, in early April, the US said again that it had struck military targets on the island, and also avoided the island's oil and gas infrastructure this time.

Iran's Mehr News Agency appeared to verify that the maritime infrastructure on the outcrop suffered little damage during the US bombing.

Military action to destroy the island's infrastructure would be hugely damaging to Iran.

It would also present a significant escalation.

It would probably send global oil prices soaring even higher and could lead to Iran targeting more energy infrastructure across the Middle East.

More than three months into the war, Iran still has the capacity to launch large numbers of low-cost, high-explosive drones at its Gulf Arab neighbours as well as at shipping vessels.

It could, potentially, expand those targets to include vital infrastructure like desalination plants that provide drinking water for millions.

Additional reporting by Gabriela Pomeroy