KABUL — Afghanistan's Defense Ministry said Saturday that a NATO airstrike in the western province of Badghis mistakenly hit a joint base housing coalition troops and Afghan security forces, killing four Afghan soldiers and three policemen.

NATO said it could not confirm whether an airstrike had hit the base.

Defense Ministry spokesman Gen. Mohammad Zahir Azimi said an Afghan army commando unit, district police members and foreign forces were in the base in the Bala Marghab district at the time of the airstrike Friday afternoon. Roauf Ahmadi, a spokesman for the western regional police commander, said the airstrike also wounded 15 Afghan soldiers and one policeman.

"During an air attack by NATO forces in Badghis province, seven Afghan forces were killed," the Defense Ministry said in a statement.

The ministry said NATO and Afghan authorities were investigating the incident and would issue a report soon.

On Friday, NATO headquarters in Kabul said more than 25 NATO and Afghan security forces members were injured during a search for two U.S. paratroopers missing from a resupply mission since Wednesday.