More than two years after US-led forces overthrew the hardline Taliban regime, attacks by remnants of the group are an almost daily occurrence in the south and east, making the rugged region effectively off-limits to foreign aid workers.

In the latest attack, suspected Taliban ambushed a security checkpoint in Nimroz province late on Friday, opening fire with machineguns and rocket-propelled grenades and killing eight Afghan soldiers, a provincial official said on Saturday.

That capped a week of violence in which at least 22 people were killed in the region, including a provincial security chief who was kidnapped and executed along with his two bodyguards and the shooting of seven Afghans, including five officials.

"Our attacks will further intensify," Hamid Agha, a Taliban spokesman, told Reuters by satellite telephone from his hideout in southern Afghanistan.

"We have done a lot of preparations and planning during the winter. Enemy losses are increasing, while ours are minimal."