A close associate of Pakistan's most wanted man, Baitullah Mehsud, who was reportedly killed in a US drone attack, has told reporters that he is alive.

Commander Hakimullah Mehsud said reports of the Taliban leader's death three days ago in an attack on a house in South Waziristan were "ridiculous".

The US government said on Friday it was increasingly confident its forces had managed to kill Mehsud.

Pakistan's foreign minister said on Friday that he was "pretty certain" Baitullah Mehsud had been killed.

But Hakimullah Mehsud said reports of his death were the work of US and Pakistani intelligence agencies.

"The news regarding our respected chief is propaganda by our enemies," he said.

"We know what our enemies want to achieve ? it's the joint policy of the [Pakistani intelligence service] ISI and FBI ? they want our chief to come out in the open so they can achieve their target."

He said the Pakistani leader had decided to adopt the tactics of Osama bin Laden and stay silent. He said he would issue a message in the next few days.

The missile fired by the US drone hit the home of the Taliban chief's father-in-law, Malik Ikramuddin, in the Zangarha area, 15km northeast of Ladha, at around 1am local time on Wednesday .

On Friday, another of Baitullah Mehsud's aides told reporters his leader had been killed in the attack.

White House spokesman Robert Gibbs described Baitullah Mehsud as "a murderous thug", saying the Pakistani people would be safer if he was dead.

"There seems to be a growing consensus among credible observers that he is indeed dead," he told reporters.

South Waziristan is a stronghold of the Taliban chief, who declared himself leader in late 2007, grouping together 13 factions in the northwest of the country.

Believed to command as many as 20,000 pro-Taliban militants, he came to worldwide attention in the aftermath of the 2007 Red Mosque siege in Islamabad – in which the security forces confronted and forcibly ejected militant students who were mostly loyal to him.

He has been blamed by both Pakistan and the US for a series of suicide bomb attacks in the country, as well as suicide attacks on western forces across the border in Afghanistan.