The US military has drawn up new plans for strikes on Iran in case President Donald Trump orders the attacks to resume. US officials familiar with the matter say the plans call for the GBU-43/B bomb, known as the MOAB or "mother of all bombs", to be used against infrastructure and nuclear sites.

This report follows our earlier story on talks about new strikes on Iran, possibly before the 3 November election. A US official and another person familiar with the talks said then that the military was preparing options to restart large-scale operations.

If the bomb is used, it will be the first time it has been used in the conflict with Iran.

One source says Trump has told the military to prepare more packages of strikes. Many of the targets are energy infrastructure sites. The plans for strikes on nuclear sites, including Pickaxe Mountain, specifically call for the MOAB.

In recent months Trump has repeatedly threatened to attack Pickaxe Mountain. The US and Israel believe Tehran has stored parts of its nuclear programme there.

The strikes could come before or after the US midterm elections. One source says the order states they must happen before the US pulls out of the area covered by US Central Command (CENTCOM). The source believes the wording hints at how the administration could carry out more strikes, declare victory and quickly withdraw all forces.

The GBU-43/B is the largest non-nuclear bomb in the US arsenal. It can destroy an area the size of 9 city blocks. After it was used in Afghanistan, a US military spokesman said the blast was about 11 tonnes of explosives.

The bomb has been used in combat only once, in 2017 in Afghanistan, against Islamic State tunnels. Work on it began in early 2002, before the Iraq war, and the first test was in 2003. GBU-series bombs have been made since the 1990s.

After release, the MOAB is steered by GPS. Because of its size, it is dropped from the rear of a US Air Force C-130 transport plane, and only the C-130 Hercules can carry it. GBU bombs were designed for surface targets, not underground bunkers. GPS guidance greatly improved their accuracy.

People familiar with internal military discussions doubt the weapon will achieve Trump's stated strategic goals or change the course of the war much. Some officials say the bomb is unlikely to penetrate deep enough. They say it will not destroy the suspected nuclear facilities at Pickaxe Mountain, which are believed to be protected by layers of granite, or other surviving nuclear sites.