A U.S. drone strike blew up a vehicle carrying “multiple suicide bombers” from Afghanistan’s Islamic State affiliate on Sunday before they could attack the ongoing military evacuation at Kabul’s international airport, American officials said. The strike came just two days before the U.S. is set to conclude a massive airlift of tens of thousands of Afghan and foreign civilians and withdraw the last of its troops, ending America’s longest war with the Taliban back in power. The U.S. State Department released a statement signed by around 100 countries, as well as NATO and the European Union, saying they had received “assurances” from the Taliban that people with travel documents would still be able to leave the country freely. The Taliban have said they will allow normal travel after the U.S. withdrawal is completed on Tuesday and they assume control of the airport. At around the same time as the drone strike, Afghan police said a rocket hit a neighborhood near the airport, killing a child. Rashid, the Kabul police chief, who goes by one name, confirmed the rocket attack, and video obtained by The Associated Press showed smoke rising from a building around a kilometer (half a mile) from the airport. The Taliban described the drone strike and the rocket attack as separate incidents, but residents of the Afghan capital heard only one large blast. Two American military officials, who spoke on condition of anonymity to discuss military operations, called the airstrike successful and said the vehicle carried multiple bombers. U.S. Navy Capt. Bill Urban, a military spokesman, said the strike was carried out in “self-defense.” He said the military was investigating whether there were civilian casualties but that “we have no indications at this time.” “We are confident we successfully hit the target,” Urban said. “Significant secondary explosions from the vehicle indicated the presence of a substantial amount of explosive material.” The strike came two days after an Islamic State suicide attack outside the airport killed at least 169 Afghans and 13 U.S. service members. The U.S. carried out a drone strike elsewhere in the country on Saturday that it said killed two IS members. President Joe Biden had vowed to keep up the airstrikes, saying Saturday that another attack was “highly likely.” The State Department called the threat “specific” and “credible.” Read:Taliban guard airport as most NATO troops leave Afghanistan