Kabul , Afghanistan -LRB- CNN -RRB- -- The head of U.S. forces in Afghanistan , General Stanley McChrystal , expressed regret Monday after more than two dozen civilians were killed in a NATO airstrike . Twenty-seven civilians died and 14 others were wounded in the incident Sunday in the central Daikondi province , according to the Afghan Interior Ministry . Ground forces at the scene found women and children among the casualties , the Afghan government and NATO 's International Security Assistance Force -LRB- ISAF -RRB- said in a joint statement . The U.S military told CNN Pentagon Correspondent Barbara Starr they `` accept '' the Afghan government 's death toll . ISAF said it had ordered an immediate investigation into the incident , while the Afghan cabinet called the attack `` unjustifiable . '' `` We are extremely saddened by the tragic loss of innocent lives , '' said McChrystal , who spoke to President Hamid Karzai Sunday evening to express his sorrow and regret over the incident . `` I have made it clear to our forces that we are here to protect the Afghan people , and inadvertently killing or injuring civilians undermines their trust and confidence in our mission . We will re-double our efforts to regain that trust . '' Commanders ordered the daylight NATO airstrike because they had specific intelligence that a group of Taliban in vehicles was heading towards coalition forces on the ground , according to a senior U.S. military official . `` Air assets picked up the movement of the vehicles and after an extensive overhead monitoring , the ground force commander ordered the strike , '' said the official , who declined to be identified because of ongoing investigations . The source would not discuss what activities the convoy took that led to suspicions it contained insurgents other than its location . The convoy of three vehicles was traveling to Kandahar province when it was struck , said Zemeri Bashary , the spokesman for the interior ministry . NATO confirmed its forces fired on the vehicles , believing that they were carrying insurgents . In a statement published in Pashtun and Dari , the Afghan cabinet said it condemned `` the repeated killing of civilians by NATO . '' An English version of the statement did not include that sentence . Civilian casualties at the hands of U.S. and NATO troops have strained relations between Afghanistan and the United States . In the last two weeks alone , more than 50 Afghan civilians are believed to have been killed in more than half a dozen U.S. and NATO military operations . The coalition is also investigating reports that several Afghan policemen were accidentally killed in an airstrike in eastern Afghanistan on February 18 . McChrystal has made avoiding civilian casualties a top priority , and he has apologized to the Afghan government for recent incidents . The numbers have dropped in recent months since McChrystal took over as U.S. commander . The U.S. military official said McChrystal is updating a directive issued to troops last summer aimed at reducing civilian casualties . The official said the intent now is to `` make it more precise and understandable by the most junior member of the force . '' Some forces have complained the directive has led to overly restrictive rules on conducting operations . Meanwhile , an influential Afghan tribal leader was among 14 people killed in a suicide attack on a meeting of tribal elders on Monday in Nangarhar province 's Khogyani district , Afghan police said according to Agence France-Presse . Haji Zaman Ghamsharik was credited with bringing relative stability to Nangarhar compared to other provinces in Afghanistan 's volatile eastern border region . Elsewhere , an insurgent rocket struck a car in Kapisa province Monday and killed one civilian , officials said . Five others were wounded in the attack . Earlier , Afghan officials had blamed the attack on a NATO ground-to-ground missile but later corrected the account . CNN 's Ben Wedeman contributed to this report