"A number of Afghan civilians were also killed and injured in the attack," General Kenneth McKenzie told reporters. "We're still working to calculate the total losses."

McKenzie said the US airlift in Kabul would continue despite the attacks.

"Let me be clear. While we're saddened by the loss of life, both US and Afghan, we're continuing to execute the mission," he said, "which is to get as many evacuees and citizens out of Afghanistan."

McKenzie said he expected IS militants to attempt further attacks but that "will not deter us from accomplishing the mission."

"We believe it is their desire to continue those attacks and we expect those attacks to continue," he said. "We're doing everything we can to prevent those attacks."

The general said more than 100,000 people had been evacuated from Kabul since August 14 -- 66,000 by the United States and 37,000 by allies.

"As of today we have approximately 5,000 evacuees on the ramp at (Hamid Karzai International Airport)," McKenzie said.

The general said two suicide bombers had detonated explosives near the Abbey Gate at Kabul airport and the nearby Baron Hotel.

He said a number of IS gunmen then opened fire on civilians and military forces.

McKenzie did not blame the Taliban for the attack, but said they need to push back their perimeter around the airport, which has been swarmed by Afghans seeking to leave following the Taliban takeover of the country.

He said the United States has shared intelligence with the Taliban on threats.

"We believe that some attacks have been thwarted by them," he said. "I don't think there's anything to convince me that they let it happen."

The US airlift is scheduled to end on August 31 with a complete withdrawal of US troops from Afghanistan.