Potential troop movements suggests Washington is weighing its optionspublished at 05:28 GMT

05:28 GMT

Paul Adams
Diplomatic correspondent

A map of Iran showing the locations of major oil and gas facilities. Black squares mark oil refineries, including one near Tehran. Blue circles mark oil terminals along Iran’s southern coastline on the Gulf, with a label identifying Kharg Island as Iran’s largest oil terminal. Neighbouring countries such as Iraq, Saudi Arabia, Qatar, the UAE are shown west of Iran, with the Caspian Sea to the north. A small inset map highlights Iran’s position on a world map.

It’s being widely reported in US media that the American military is sending additional forces to the Gulf, including what’s known as an amphibious ready group (ARG), with up to 5,000 Marines and sailors.

The amphibious assault ship USS Tripoli will join the substantial armada already operating off the coast of Iran.

It’s not clear which other vessels will accompany the Tripoli, but an ARG typically includes ships capable of carrying landing craft, as well as large numbers of helicopters.

The latest deployments suggest the Pentagon is considering an expanded range of options. These could include protecting commercial shipping in the Strait of Hormuz and conceivably some kind of limited amphibious landing.

One possible objective is Iran’s tiny Kharg Island, in the northern Gulf.

Lying 22 miles off the Iranian mainland, Kharg is a vital oil hub, where tankers have been seen filling up with Iranian oil since the war began two weeks ago.