The US military has dropped the largest non-nuclear bomb on an Islamic State cave complex in Afghanistan.

In a statement, the US Forces Afghanistan said the GBU-43/B Massive Ordnance Air Blast bomb hit a tunnel complex in the Achin district in Nangarhar province, close to the border with Pakistan at around 7.32pm local time.

Pentagon spokesman Adam Stump said that it was the first time the weapon has been used in combat, reports AFP.

The GBU-43 bomb contains 11 tonnes of explosives and is the US military's largest non-nuclear device. It is nicknamed 'the mother of all bombs' - an acronym given by the US Air Force - on its proper name, the Massive Ordnance Air Blast bomb.

The weapon was developed during the Iraq War. Its deployment was signed off by General John Nicholson, the commander of the US forces in Afghanistan.

The military said it is still assessing the damage the bomb has caused.