AFGHANISTAN (CNN) -- The US military has dropped an enormous bomb in Afghanistan according to four US military officials with direct knowledge of the mission.

A GBU-43/B Massive Ordnance Air Blast Bomb — nicknamed the "Mother of All Bombs" (MOAB) — was dropped in at 7 p.m. local time Thursday, sources said.

This is the first time a MOAB has been used in the battlefield, according to the US officials.

Military sources said the target was ISIS tunnels and personnel in the Achin district of the Nangarhar province.

The military is currently assessing the damage.

This munition was developed during the Iraq War but was never used in the battlefield.