Islamic State on Monday claimed responsibility for an attack on Taliban forces in Kabul.
The militant group said on Telegram that the attack on Sunday had killed 20 people and wounded 30.
A spokesman for Afghanistan's Taliban-run interior ministry said an explosion outside the military airport in the capital Kabul had caused multiple casualties.
The interior ministry denied the casualty figures claimed by Islamic State and said it would release the official death toll.
Islamic State has claimed several high-profile attacks in Kabul, including the storming of a hotel that caters to Chinese businessmen and a shooting at Pakistan's embassy that Islamabad called an assassination attempt against its ambassador, who escaped unharmed.