The United States is considering using its biggest non-nuclear bomb against Iran if President Donald Trump should decide to renew combat in the war that has hit a deadlock, CNN reported on Thursday.

The military is planning for the potential use of the GBU-43/B Massive Ordnance Air Blast (MOAB) bomb — better known by its nickname, the “Mother Of All Bombs” — to target Iranian energy infrastructure and nuclear sites, according to the news outlet, which quoted officials familiar with the matter.

Trump is trying to boost his low approval ratings ahead of November’s midterm elections, with polls showing the unpopular war in Iran and fuel and other price rises it has caused are hurting his Republican Party.

Diplomatic efforts to end the conflict, which erupted with US-Israeli strikes on Iran in February, have been at an impasse since the summer.

But officials have raised doubts over the efficacy of the bomb if it were deployed, particularly its ability to destroy suspected underground nuclear sites in the Islamic republic.

“The MOAB is a massive information operation type weapon that is great for huge area clearance but not much else,” a source familiar with the plans told CNN.

“It is definitely not designed as a deep penetration warhead.”

The United States and Israel have said the war was necessary to prevent Iran from acquiring nuclear weapons — a goal Tehran has long denied pursuing.

There are also concerns over the possibility of civilian casualties from such a huge weapon.

Washington has in recent weeks dialed back military operations in favour of economic pressure.

AFP has contacted the Pentagon for comment.

In 2017, the US military in Afghanistan dropped the “MOAB” to target Islamic State group hideouts in a complex of tunnels and bunkers, killing more than 90 militants.