An Afghan official says a roadside bombing has killed seven civilians in a northern province.

District chief Ahmad Lemar Osmanyar says the victims were all relatives and they were travelling in a car to a wedding ceremony on Tuesday when their vehicle struck a bomb in Parwan province sometime around noon.

The attack took place in Sayedkhail district, which is a relatively secure area in Parwan.

Osmanyar says an investigation is underway. No group has immediately claimed responsibility for the attack, but the Taliban have stepped up their attacks against Afghan security forces across the country.