Dadullah, a top lieutenant of Taliban leader Mullah Omar, was killed Saturday in the southern province of Helmand, said Said Ansari, the spokesman for Afghanistan's intelligence service.

Nato's International Security Assistance Force did not confirm the death.

"It certainly is an issue that we're tracking," said spokesman Maj. John Thomas. "But it's not our issue, it's an Afghan issue."

Dadullah would be one of the highest-ranking Taliban leaders to be killed since the fall of the hardline regime following the US-led invasion in 2001, and his death would represent a major victory for the Afghan government and US and Nato troops.

Kandahar Gov. Asadullah Khalid said Dadullah, who had only one leg, died during an operation by US-led coalition, Nato and Afghan troops.

"Mullah Dadullah was the backbone of the Taliban," Khalid said. "He was a brutal and cruel commander who killed and beheaded Afghan civilians."

Khalid showed Dadullah's body to reporters at a news conference in the governor's compound. An Associated Press reporter said the body, which was lying on a bed and dressed in a traditional Afghan robe, had no left leg and three bullet wounds: one to the back of the head and two to the stomach.

The AP reporter said the body appeared to be Dadullah's based on his appearance in TV interviews and Taliban propaganda videos.

But Qari Yousef Ahmadi, a purported Taliban spokesman, denied that the Taliban commander had been killed.

"Mullah Dadullah is alive," Ahmadi told AP by satellite phone. He did not give further details.

In Khost around 55 Taliban militants were killed in two separate battles with Afghan and international forces in eastern Afghanistan, a governor told AFP yesterday.

Up to 40 were killed in a battle on Saturday in Paktika province's Gayan district, close to the border with Pakistan, provincial governor Mohammad Akram Ikhpolwak said.

Fifteen others were killed in similar fight on Saturday in adjoining Barmal district, also on the border, he said.

The toll was the highest in the region since Nato-led and Afghan forces in January bombed groups of militants spotted crossing from Pakistan, killing 150 of them.