KANDAHAR, Afghanistan - A roadside bomb killed five Afghan security forces and wounded four as they patrolled with NATO troops in southern Afghanistan, an army chief said Thursday.

The blast happened in Uruzgan province on Wednesday evening, said regional Afghan army commander Gen. Rehmatullah Raufi. He blamed Taliban militants.

The explosion wrecked a vehicle carrying Afghan forces and no NATO troops were hurt, he said.

In a text message to an Associated Press reporter, purported Taliban spokesman Qari Yousef Ahmadi said its militants had launched the attack using a remote-controlled landmine.

Militant supporters of the Taliban have recently stepped up attacks on Afghan and western forces, sparking the bloodiest fighting since the fall of the hardline regime five years ago.