A map shows the location of Bagram Airfield in Afghanistan.
VON PRESS Asia & Pacific: The blast ripped through Bagram Airfield in Afghanistan, causing a number of casualties, the NATO mission to the country said in a statement.
"We can confirm that there was an explosion at Bagram Airfield just after 5:30 am .There have been casualties," the statement of the Resolute Support mission read.
"Our Force Protection and medical teams are responding to the situation," it added, without providing additional details.
No militant group has reportedly taken responsibility for the attack.
Abdul Shakoor Quddusi, the head of Bagram district, said three people were killed and 15 others were wounded in the "powerful blast", but could not confirm the nationalities of the victims.
"It is not clear what caused the explosion or the nationality of the victims," Quddusi told the CNN broadcaster.
Bagram Airfield, the US' largest military base in the conflict-ridden country, is not new to terrorist attacks.
Last December, suicide bomber riding a motorcycle killed six American troops, AFP reported.
It was one of the deadliest attacks on foreign troops in the country in 2015.