American drone strike hit a vehicle carrying multiple Islamic State suicide bombers heading for the Kabul airport on Sunday afternoon, US Central Command spokesperson Bill Urban said, adding that a substantial amount of explosive material was present in the vehicle.

"US military forces conducted a self-defense unmanned over-the-horizon airstrike today on a vehicle in Kabul, eliminating an imminent ISIS-K threat to Hamid Karzai International Airport. We're confident we successfully hit the target," Urban said in a statement.

"Significant secondary explosions from the vehicle indicated the presence of a substantial amount of explosive material. We are assessing the possibilities of civilian casualties, though we have no indications at this time," he added.

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This is the second airstrike the US has conducted against ISIS-K, which claimed responsibility for the suicide bombing attack at the Kabul airport gate last Thursday that killed 13 US service members and scores of Afghans struggling to flee the country and escape the new Taliban rule.

Warning ISIS-K, US President Joe Biden on Saturday vowed to keep up airstrikes against them while also outlining the threat of another "highly likely" terror attack this weekend.

"This strike was not the last. We will continue to hunt down any person involved in that heinous attack and make them pay," he said in a statement on Saturday. 

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Meanwhile, there have also been reports of a rocket strike at a house near the airport on Sunday. The rocket strike reportedly killed a child. However, it wasn’t clear if the two explosions on Sunday were connected. 

The airstrike came as the US winds down a historic airlift that saw tens of thousands evacuated from Kabul’s international airport. National security adviser Jake Sullivan said on Sunday that  approximately 300 American citizens remain in Afghanistan who want to leave before President Joe Biden's Tuesday deadline for evacuations.