The Taliban has claimed responsibility for an explosion at the NATO air base at Bagram, north of the Afghan capital of Kabul.
The NATO-led Resolute Support mission issued a statement saying the November 12 attack killed four people and injured at least 14.
The victims were not identified.
The statement said that just after 5:30 a.m. local time an explosive device detonated on the base and that force-protection and medical teams were at the scene.
There were no further details, but local media reported that a man posing as a laborer got access to the base and detonated a suicide vest. If these reports prove true, it would represent a significant security breach at one of the most heavily protected installations in the country.
Taliban spokesman Zabihullah Mujahid posted a statement on Twitter claiming responsibility for the blast.
Bagram has frequently come under attack by Taliban insurgents.
Last December, a motorcycle-riding Taliban suicide bomber killed six U.S. soldiers near the base, Afghanistan's largest.
It was one of the deadliest attacks on foreign troops in the country in 2015.
Late on November 10, the Taliban carried out a suicide attack in the northern city of Mazar-i-Sharif that killed four people and wounded more than 100.
About 10,000 U.S. troops are stationed at Bagram on a mission to support and train Afghan security forces.
Based on reporting by Reuters, dpa, and AFP