NATO says two rockets fired at insurgents missed their target and killed 12 civilians in southern Afghanistan.

Gen. Stanley McChrystal, the top NATO commander in Afghanistan, has apologized to Afghan President Hamid Karzai for the accident.

In a statement released Sunday by NATO, McChrystal says the current massive military offensive in Helmand province is aimed at restoring security and stability to the country's dangerous south and he regrets that innocent lives were lost in Nad Ali district.

Karzai issued a statement minutes earlier saying 10 members of the same family died when a rocket hit a house. Before the offensive began Saturday, Karzai pleaded with Afghan and foreign military leaders to be extra careful to avoid civilian casualties.