The Pentagon says there was an explosion outside Kabul airport.
Spokesman John Kirby said there was no immediate word on casualties in the blast Thursday.
Thousands of Afghans have been gathered at the airport for days trying to flee the country since the Taliban takeover earlier this month.
Western nations had warned Thursday of a possible attack on Kabul’s airport in the waning days of a massive airlift, as thousands of Afghans desperate to flee Taliban rule continued to flock to the gates.
Several countries urged people to avoid the airport, where an official said there was a threat of a suicide bombing. But just days — or even hours for some nations — before the evacuation effort ends, few appeared to heed the call.
Over the last week, the airport has been the scene of some of the most searing images of the chaotic end of America's longest war and the Taliban's takeover, as flight after flight took off carrying those who fear a return to the militants' brutal rule.
This breaking news story will be updated.