NATO says an airstrike against suspected insurgents has killed five civilians in Kandahar province in southern Afghanistan.

Monday's accident follows the deaths on Sunday of 12 Afghans, who were killed by two U.S. rockets in neighboring Helmand province. Some 15,000 U.S., Afghan and other international forces are in Helmand on the third day of a major offensive to reclaim the town of Marjah from Taliban control.

Civilian casualties are a sensitive issue in the eight-year-old war.

A NATO statement says a joint patrol of NATO and Afghan troops saw individuals digging along a path in the Zhari district of Kandahar province and mistakenly concluded that they were planting an improvised explosive device. Two civilians were wounded in the strike.