Mullah Dadullah, one of two top Taliban commanders the government said had been surrounded in the fighting, telephoned Reuters to say that only seven or eight guerrillas had been killed, including one commander, Mullah Mohammad Easa.

Speaking by satellite phone from an undisclosed location, Dadullah said the guerrillas had killed about 20 Afghan police and army troops and 14-18 from the U.S.-backed foreign force hunting militants in Afghanistan.

"The government was claiming that it killed 178 Taliban," he said. "That is not true."

"The government was claiming that it had surrounded Mullah Dadullah, Mullah Brother, Mullah Adbul Hanan, Mullah Abdul Basir and Mullah Abdul Hakim and that they would soon arrest or kill them," he said. "This was completely wrong."

The Defence Ministry said on Thursday that Dadullah and Brother, members of the Taliban leadership council led by elusive Taliban leader Mullah Mohammad Omar, and the three other commanders were surrounded in an area where the provinces of Kandahar, Uruzgan and Zabul meet.

It later said they appeared to have escaped.

The government has said that most of the guerrillas were killed by U.S. air strikes, in what by its figures would have been one of the bloodiest setbacks for the Taliban since their 2001 overthrow by U.S.-led forces.

It said three of its troops were killed in the operation and three hurt, while the U.S. military said six of its soldiers were slightly wounded.

Dadullah also said the guerrillas had shot down two U.S. helicopters in the fighting.

The U.S. military said two of its Chinook helicopters were damaged by small-arms and rocket-propelled grenade fire during fighting on Tuesday and one had to make an emergency landing, but both returned to base without casualties.

The U.S. military on Wednesday gave an estimate of 40-50 guerrillas dead in the fighting but then referred reporters to the Afghan authorities for updates on casualties.

U.S.-led forces ousted the Taliban government after it refused to hand over Osama bin Laden, mastermind of the Sept. 11 attacks on the United States, but three-and-a-half years on, they have been unable to subdue the insurgency or catch bin Laden.

U.S. and Afghan forces have reported killing more than 200 insurgents in the past week alone and nearly 400 since March as they move to prevent guerrilla efforts to derail Sept. 18 parliamentary elections.