DENVER (KDVR) — Two suicide bombers and gunmen attacked crowds at Kabul’s airport Thursday, killing at least 60 Afghans and 13 U.S. troops, according to U.S. and Afghan officials.

The terrorist group ISIS-K is claiming responsibility for the attack. ISIS-K is an Afghanistan-based breakaway of the Islamic State that emerged in Syria and Iraq in 2014, according to Nader Hashemi, Director for the Center of Middle East Studies at University of Denver.

“ISIS-K views the Taliban as too moderate. They criticize the Taliban for striking a deal with the United States. They have a much more radical and extremist agenda,” Hashemi said.

Hashemi said ISIS-K was established within the last several years but already has a reputation for carrying out what he calls “barbaric attacks.”

“They view the Taliban as their enemy. There have been clashes, and I suspect as a result of today’s event, there are going to be increasing tensions between the Taliban and ISIS-K, because this is an embarrassment for the Taliban who want to present themselves as the new government of Afghanistan,” Hashemi said.

The attack comes in the final days of U.S. airlifts for those fleeing the Taliban takeover. Hashemi said the attack will complicate the already difficult task of getting people out.

“This changes the evacuation equation radically. It’s impossible to approach safely the Kabul airport because there’s fear of more attacks,” Hashemi said.

As American troops are slated to pull out by the end of August, Hashemi said the Taliban faces a tall order of reigning in control and defeating ISIS-K.

“As the result of the attack, there’s actually a convergence of interests between the United States and the Taliban. Now, they have a common enemy and that enemy is ISIS-K,” Hashemi said.