Taliban commander Mullah Mohammad Hassan Rahmani told the Reuters news agency that nine U.S. soldiers were killed, but his claim could not be independently confirmed.
The U.S. military on 13 February said one of its vehicles struck a bomb in southwest Afghanistan, killing four American troops. The military said the blast occurred in Oruzgan Province as troops were patrolling in an armored Humvee.
Rahmani, a former Taliban governor of Kandahar Province, said guerrillas will step up attacks once the winter cold abates.
Fighting in Afghanistan traditionally eases off during the winter when mountain passes get snowed under.