The police deputy chief, Ghulam Rasool, was driving through the area to warn of an impending militant attack on police posts when his vehicle was hit by a rock-propelled grenade near Qalat city, regional government spokesman Ali Khail said.

Also in Zabul, rebels battled U.S. forces, though it was not immediately clear whether there were any militant casualties, said coalition spokesman Maj. Quentin Innis.

In recent weeks, Afghanistan has seen some of the deadliest fighting since the ouster of the Taliban regime in late 2001. Militants have stepped up attacks, particularly in the south, drawing a fierce response from coalition and Afghan forces.