Government forces in Afghanistan have launched a military offensive with the help of American air support against fighters loyal to the Islamic State in Nangarhar Province, Afghanistan.

The effort comes at the same time U.S. General John Nicholson, commander of all international troops assigned to Operation Resolute Support, has requested additional U.S. soldiers to serve as advisers to the Afghan government.

The Islamic State in Iraq and the Levant — Khorasan Province, ISIL’s Afghanistan branch, consists of a number of terrorist groups which share overlapping abilities, territory, and fighters. Announcing their formation in January 2015, ISIL-K began as a confluence of leadership and fighters from the Afghan and Pakistani Taliban.

ISIL-K numbers around 1,000 fighters, almost exclusively within Nangarhar Province in Afghanistan, with other members of the group operating in the tribal regions of Northwest Pakistan. Its fighters are opposed to both the Afghan Taliban and Al-Qaeda. The group has conducted suicide bombings and shooting attacks in both Afghanistan and Pakistan, most notably the July 2016 suicide bombing in Kabul which left 80 people dead.