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.

A major offensive was launched last summer to clear a number of districts within Nangarhar province following the Kabul bombing. During that operation, five Green Berets were wounded.

Since then, it’s not clear how well government forces have contained ISIL-K. Last July, General Nicholson said that Afghan government and U.S. actions had reduced ISIL-K’s numbers from 3,000 to 1,500.

The Afghanistan-Pakistan border region has long been a haven for competing jihadist and criminal elements, dating back to the Soviet-Afghan War. Warlords have curried favor from armed elements through a combination of money, force, and religious and political ideologies. The Islamic State’s primary justification for establishing an IS presence in the region centered on the Taliban and Al-Qaeda’s pandering to tribal customs in the region, cooperating with the Pakistani Intelligence Service, and other offenses to their strict interpretation of Sharia.

ISIL-K’s rivalry with the Afghan Taliban and Al-Qaeda has undoubtedly limited the scope of their operations and their ability to attract recruits.