A US Army Chinook helicopter lands on a hill in Kabul on November 7, 2009The Afghan government says a NATO air strike has mistakenly killedseven members of the Afghan security forces in Badghis province.  

NATOand Afghan forces are investigating the incident in western Afghanistanthat killed members of the country's army and police.

Earlier,NATO said 25 international and Afghan soldiers were wounded in thearea. Officials initially blamed "insurgent activity" for thecasualties, but later said it was possible the soldiers were hit byfriendly fire.

Afghanistan's Interior Ministry spokesman Zamary Bashary tells VOA that this is a sad incident.

"Wehave lost forces that are fighting in order to bring security forAfghanistan.  But such attacks will never deter our partnership .  This is clear that this was a mistake," he said.

Headded that incidents such as this one are rare, especially after theUnited States imposed new restrictions on air strikes in an effort toavoid civilian casualties.

"The new strategy actually has worked, and it has reduced the number of civilian casualties," he said.

The troops were conducting an operation to find two missing U.S. soldiers who are believed to have drowned.

Localpolice officials say the two soldiers were swept away Wednesday whiletrying to save supply boxes that fell into the water after beingair-dropped.

This year has been the deadliest for international troops in Afghanistan since the fall of the Taliban-led government in 2001.