US President Donald Trump has indicated that he may send troops to seize control of Iran's key oil export terminal at Kharg Island in the northern Gulf. So what's behind this, how would it work and what are the risks?

Kharg Island has long been Iran's chief outlet for its oil exports. The island sits offshore with waters deep enough to load product onto tankers known as Very Large Crude Carriers (VLCCs), which can hold around two million barrels. Around 90% of Iran's oil exports pass through Kharg.

During the Iran-Iraq war in the 1980s it was frequently bombed by the Iraqi Air Force and on 13 March this year the US struck what it said were 90 military targets on the island. It however spared the oil infrastructure.

If the US does decide to invade Kharg Island then it would most likely be a temporary measure intended to put pressure on Iran by cutting off its fuel exports until it relinquished its chokehold on the Strait of Hormuz - one of the world's busiest oil shipping lanes - and conceded to Washington's demands.

Given the resilience and defiance of the Iranian regime it is highly questionable whether this would work. The speaker of Iran's parliament, Mohammad Bagher Ghalibaf, has warned that his country's forces would rain down fire on any invading US forces. Iran is believed to have reinforced its defences on the island, including with surface-to-air missile batteries.

Iran has accused the US of duplicity by proposing peace talks at the same time as dispatching troops to the region, comprising nearly 5,000 US Marines and around 2,000 paratroopers from the 82nd Airborne Division.

In theory, the paratroopers could make an airborne assault, probably at night, to seize key positions on this small island. The US Marines would deploy from ships equipped with Osprey tilt-rotor aircraft and Landing Craft Air Cushioned (LCAC) for making amphibious landings. However, they would first need to navigate the Iranian-controlled Strait of Hormuz, which is fraught with danger from Iranian drone and missile launch sites.

Any landing, by air or sea, would expect to be met with anti-personnel mines and swarms of drones. Although the US force would almost certainly prevail, it could incur significant casualties.

Moreover, holding the ground amidst Iranian bombardment from the mainland would pose significant challenges. Any prolonged US occupation of Iranian territory would likely meet with domestic opposition in the US, including from Trump's supporters who favored a non-involvement strategy in foreign conflicts.

Finally, the surrounding situation remains fluid with discussions ongoing about potential peace talks between the US and Iran, suggesting that any aggressive action might also serve as a diversionary tactic. With various other islands in the Gulf presenting alternative targets, the strategic landscape is complex and the stakes are high.