Smoke rose after a blast in Kabul on Sunday.
U.S. officials said an American drone strike targeted a suspected suicide bomber traveling in a vehicle to attack the city's airport.
The strike is the second carried out by U.S. forces in Afghanistan after an Islamic State suicide bomber attacked the airport last week, killing 13 American troops and scores of Afghan civilians.
ISIS operatives in Afghanistan are viewed as a threat by both Western forces and Taliban militants who recently took control of the country.
The violence comes as the U.S. nears the August 31 deadline to pull all American forces from Afghanistan, ending a 20-year military mission.
President Joe Biden and First Lady Jill Biden visited Dover Air Force Base in Delaware on Sunday to honor the 13 Americans killed in the ISIS blast last week.
He received the service members' remains that were being flown back to the United States.
Biden pledged to end American's longest war, but the rapid and chaotic withdrawal has drawn criticism.
The United States and allies have taken about 114,400 people - foreign nationals and vulnerable Afghans - out of the country in the past two weeks.
Philadelphia's International Airport welcomed Afghan refugees over the weekend. The city's mayor greeted the arrivals, who received COVID-19 tests and welcome packages of water, food, toiletries and diapers.
Many will stay in Philadelphia and surrounding areas.
Others are fleeing overland. An Iranian health official said over 1,000 people a day were coming through the Dogharoun crossing.
The United Nations refugee agency said last week up to half a million Afghans could flee their homeland by year-end.