The Islamic State group claimed responsibility for a deadly suicide attack at the airport in Kabul on Thursday during the US-led evacuation from Taliban-ruled Afghanistan, the SITE monitoring agency said.
The bomber "was able today to penetrate all the security fortifications" and get within "five meters (16 feet)" of US forces before detonating his explosives belt, the jihadist group's propaganda arm Amaq said, according to a translation by SITE.
The statement only appeared to mention one bomber and one blast. At least two bombs are believed to have detonated during Thursday's attack at the airport.
The United States and other Western powers taking part in the evacuation had warned for several days of threats by the Islamic State's regional arm in Afghanistan.
Tens of thousands of Afghan citizens have been waiting outside the airport since the Taliban took power in the country on August 15, fleeing amid fears of reprisals and a return of the Islamists' brutal interpretation of Islamic law.
Foreign nations are also rushing to evacuate their staff and citizens from the country ahead of an August 31 deadline set by US President Joe Biden for the full withdrawal of American troops from the country.
The Afghan branch of IS, known as the Islamic State in Khorasan Province, first gained a foothold in eastern Nangarhar province in 2015, but has come under pressure in recent years from the US-led coalition, the Afghan army and the Taliban itself.
It has retained the ability to carry out devastating attacks in Kabul, however.
General Kenneth McKenzie, head of US Central Command, told reporters before the claim of responsibility that once the United States confirmed who was behind the attack "we will go after them."
He also said that the threat of more attacks, including a vehicle bomb, remained "imminent," and warned that the group would also like to attack one of the dozens of aircraft flying in and out of the airport as the evacuation continues.