US and Nato troops are battling Taliban fighters in southern Helmand province [File: EPA]

At least 15 civilians have been killed after a roadside bomb exploded in southern Afghanistan's Helmand province, the governor's office has said.

The victims were travelling in a vehicle that drove over the device in the Khan Neshin district on Friday, according to a statement released on Saturday.

"The blast killed 15 civilians and wounded another four," Daud Ahmadi, a provincial spokesman, told the AFP news agency. He said that a number of children were among the dead.

He said the "barbaric attack" was the work of "enemies of Afghanistan," a term often used to refer to Taliban fighters.

Improvised explosive devices (IEDs), which are crude, cheaply made and difficult to detect, are regularly placed in areas where they might kill or maim US, NATOo or Afghan security forces.

US and NATO troops are fighting the Taliban for control of the southern province.

Increasing violence

Also Saturday, a suicide bomber blew up a stolen police car that had been packed with explosives, injuring five Afghan soldiers and nine civilians near an army checkpoint in northern Afghanistan.

Muhbobullah Sayedi, the spokesman for the governor of Kunduz province, said the force of the blast Saturday morning destroyed several nearby homes.

Afghanistan is suffering some of the worst violence in the nine-year conflict, with 1,271 civilians killed in the first six months of 2010, according to UN figures. That figures is a 21 per cent increase on the same period last year.

This year has also been the deadliest for foreign troops with about 680 troops being killed so far, compared to 521 for all of 2009.

More than 140,000 foreign troops are deployed in Afghanistan, mostly in the south and east of the country, but they hope to hand over control over security to local forces by 2014.

Source: Agencies