A government official says a roadside bomb has struck a car in southern Afghanistan, killing six civilians.

The spokesman for the governor of southern Helmand province said Saturday two women and four men were killed in the blast in the Nad Ali district.

Spokesman Ahmad Zeerak says those killed were all "innocent civilians and from one family." He says they were driving home from a nearby village in their own car when the explosion occurred at about 7 p.m. Friday.

Helmand province has been the focus of several U.S.-led offensives, but it remains one of the most dangerous areas in the country.