They happened near a gate where American troops and civilians have gathered in recent days.
The airlift from the international airport continued even after the explosion took place.
Pentagon spokesman John Kirby tweeted that the explosion at Abbey Gate was the result of a “complex attack” that resulted in a number of U.S. and civilian casualties.
Kirby confirmed at least one other explosion at or near the Baron Hotel, which is near the Abbey Gate.
Thousands of U.S. and Afghan citizens have been at the airport looking to flee the country since the Taliban seized power earlier this month.
White House officials tell NBC News that President Biden was briefed on the Kabul blast.
The U.S. embassy in Kabul issued an alert about the explosion, saying there were reports of gunfire in the area.
The embassy advised U.S. citizens to avoid traveling to the airport or leave the gates if they are there.
The U.S. and other western nations had warned of a possible attack on Kabul’s airport in the final days of massive evacuation efforts.
Several countries had urged people to avoid the airport, where an official said there was a threat of a suicide bombing.