KABUL – A massive explosion struck the largest US military base in Afghanistan early Saturday, causing some casualties, Nato confirmed.

“We can confirm that there was an explosion at Bagram Airfield this morning just after 5:30 am. There have been casualties,” the military coalition said in a brief statement.

The Afghan defence ministry said it was aware of the explosion but could not immediately confirm the casualties.

On the other hand, head of Bagram district 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.

No group has yet claimed responsibility for the blast, which rattled the city days before the start of winter season.

The area has been under constant threat from miscreants who targeted it in past as well.