NATO says 12 Afghan civilians dead in missile strike

KABUL (Reuters) - Rockets fired at militants attacking NATO and Afghan troops missed and killed 12 civilians during an offensive in the southern Helmand province targeting a Taliban stronghold, NATO forces in Afghanistan said Sunday.

"It's regrettable that in the course of our joint efforts, innocent lives were lost. We extend our heartfelt sympathies and will ensure we do all we can to avoid future incidents," U.S. General Stanley McChrystal, the NATO commander, said in a statement.

Afghan President Hamid Karzai expressed sadness at the incident. He had urged NATO to exercise caution during the offensive to prevent civilian casualties.

"Upon hearing the news, Hamid Karzai immediately ordered an investigation as he had previously ordered that the operation should be carefully done to prevent innocent civilians being killed," a statement from the president's office said.

(Reporting by Bryson Hull; Editing by Michael Georgy)