A Japanese expert who specializes in peacebuilding in the Middle East says the regional arm of the Islamic State militants has been active in Afghanistan since about 2014.
Higashi Daisaku, a professor at Sophia University in Tokyo, told NHK that the group is targeting both US influence in the world as well as the Taliban.
In an interview, Higashi said, "The group has a very strong hostile attitude toward the Taliban. So the group wanted to attack the airport to damage both the Taliban and the United States right now, with the Taliban about to begin to establish its regime."
Higashi also said the US has repeatedly issued warnings of possible terrorist attacks, which has now become a reality.
He said, "After the launch of a new administration in Afghanistan, the challenge for the Taliban will be figuring out how to prevent this kind of attack targeting Afghan civilians."
The professor said that any further attacks would force the Taliban to face questions about its ability to control the country.