Kabul, Afghanistan - A top Taliban military commander described as a close associate of Osama bin Laden and Taliban leader Mullah Omar was killed in an airstrike this week close to the border with Pakistan, the US military said Saturday. A purported Taliban spokesman denied the claim.

This undated photo, which has been handed out by the US military shows Mullah Akhtar Mohammad Osmani. [AP]

Mullah Akhtar Mohammad Osmani was killed Tuesday by a US airstrike while traveling by vehicle in a deserted area in the southern province of Helmand, the US military said. Two associates also were killed, it said.

Osmani, regarded as one of three top associates of Omar, is the highest-ranking Taliban leader that the coalition has claimed to have killed or captured since US forces deployed in Afghanistan to oust the Taliban regime in late 2001 for hosting bin Laden.

There was no immediate confirmation from Afghan officials or visual proof offered to support the American claim. A US spokesman said that "various sources" were used to confirm Osmani's identity.

A purported Taliban spokesman, Qari Yousef Ahmadi, denied that Osmani had been killed, saying that the airstrike instead killed Mullah Abdul Zahir, a group commander, and three other Taliban fighters.

"I confirm that Osmani is alive and is in Afghanistan," Ahmadi told The Associated Press by phone from an undisclosed location.

US military spokesman Col. Tom Collins said that officials waited four days to announce the news in part so that they could be sure it was Osmani who died in the strike.

The Taliban's chief military commander in southern Afghanistan, Osmani played a "central role in facilitating terrorist operations" including roadside bombs, suicide attacks and kidnappings, the US said.

"This guy had been deeply involved in terrorist acts against the people of Afghanistan, NATO and the government," Collins said. "He was a top commander of Taliban operations in the south, and now he's no more."

The Taliban militia has stepped up attacks this year, particularly in southern Afghanistan, and waged fierce battles with Western and Afghan forces. About 4,000 people have died in the violence, raising fears for the country's future.

Osmani was part of a group of "co-equals" at the top of the Taliban leadership chain just under Omar, Collins said. He was also in charge of the Taliban's finances, he said.

Collins said that Osmani had been "utilizing both sides" of the Afghan-Pakistan border, and that the US military had been tracking him "for a while."

"When the time was right, and we thought we had a good chance of hitting him without causing any harm to civilians, we struck," he said.

Though the US said Osmani was an associate of bin Laden, Omar and Afghan insurgent leader Gulbuddin Hekmatyar, Collins said he didn't know the last time Osmani had contact with any of the three.

During the Taliban regime, Osmani was the corps commander of Kandahar, the militia's seat of power.

More recently, he was regarded as one of the top three Taliban leaders under Omar, along with another senior military commander in the south and southeastern regions, Mullah Dadullah, and influential policymaker Mullah Obaidullah.

In June, a man claiming to be Osmani, his face was concealed by a black turban, gave an interview to a Pakistani television network in which he said Omar and bin Laden were alive and well. He claimed to be receiving instructions from Omar.