Thirty six Islamic State (Isis) militants were killed when the US forces dropped GBU-43/B, the biggest non-nuclear bomb ever used in a conflict, in Afghanistan's Nangarhar province. The Afghan defence ministry said no civilians were affected by the bombing and the Kabul administration was kept in the loop regarding the attack.

Pentagon had earlier announced that GBU-43/B device – colloquially known in the military circles as the 'mother of all bombs' – was used for the first time in a combat on Thursday, 13 April. The 9,800kg powerful explosive targeted a tunnel complex used by the Isis insurgents, who have been gaining a foothold in Afghanistan in the last few years.

"The air strike was designed to support the efforts of the ANSF [Afghan National Security Forces] and US Forces as well as minimise the risk to ANSF and the US Forces conducting clearing operations in the region," read a statement from the Afghan presidential palace. Kabul authorities said precautionary measures were taken to avoid civilian casualties in the region.

The blast occurred at about 7.30pm local time in the Nangarhar province's Achin district after the 30ft GPS-guided massive bomb was dropped from an MC-130 aircraft.

The GBU-43/B Massive Ordnance Air Blast Bomb, primarily designed to destroy underground targets, wiped out a large cache of weapons when it struck a network of caves used by the Isis. The weapon was built during the Iraq war and tested in 2003 but never put into combat use.

The escalation in Afghanistan sends a powerful message as it follows similar sudden strikes in Syria, which targeted President Bashar al-Assad's key airfield. The assault on Isis has also come as a warning by the Donald Trump administration to recalcitrant states like North Korea, which is widely suspected to be on the verge of carrying out yet another nuclear test.

When asked whether this major anti-Isis bombing is a thinly-veiled message to North Korea, US President Donald Trump responded: "I don't know if this sends a message; it doesn't make any difference if it does or not. North Korea is a problem, the problem will be taken care of."

Afghanistan 'mother of all bombs'
The GBU-43/B Massive Ordnance Air Blast (MOAB) bomb is pictured in this undated handout photo Reuters