Baitullah Mehsud, the leader of the Taliban in Pakistan who was long suspected to have been behind the assassination of former prime minister Benazir Bhutto, has reportedly been killed in a U.S. air strike.

Mehsud is believed to have died after a missile strike on his father-in-law's house in South Waziristan on Wednesday. His wife also died in the attack.

Intelligence sources in both the U.S. and Pakistan have confirmed that the CIA is behind the fatal missile attack.

On Friday, Taliban commander Kafayat Ullah told The Associated Press that he could confirm the militant leader's death.

"I confirm that Baitullah Mehsud and his wife died in the American missile attack in South Waziristan," he said in a telephone interview.

Ullah did not give any further details on Mehsud's death.

A local tribesman said Mehsud was being treated for kidney pain in his father-in-law's house at the time of the attack. The tribesman claimed to have attended the Taliban leader's funeral.

Earlier Friday, Pakistani officials said their intelligence indicated that Mehsud had been killed, though they intended to visit the site of the attack to verify his death.

"To be 100 per cent sure, we are going for ground verification," said Foreign Minister Shah Mahmood Qureshi. "And once the ground verification reconfirms, which I think is almost confirmed, then we'll be 100 per cent sure.

Pakistani intelligence officials told The Associated Press that reports suggested Mehsud was dead and buried in the South Waziristan village of Nardusai, though authorities have not seen the body.

White House Press Secretary Robert Gibbs said the U.S. could not confirm the Mehsud was dead, but described the Taliban leader as a murderous thug.

"If he is dead, without a doubt, the people of Pakistan will be safer as a result," Gibbs said Friday.

Mehsud had strong al Qaeda connections and was long considered Pakistan's top internal threat.

He also held ties to militant groups in Afghanistan, where his fighters occasionally assisted insurgent leader Siraj Haqqani.

Afghan Defence Ministry spokesperson Gen. Mohammad Zahir Azimi called Mehsud "an international terrorist that affected India, Pakistan and Afghanistan," though he did not confirm that the Taliban leader was dead.

In June, Pakistan announced that it intended to launch an operation in South Waziristan, targeting Mehsud. He was long considered the number one suspect in the assassination of Bhutto, by both the CIA and the former Pakistani government. And his Taliban fighters killed hundreds of Pakistani citizens through their attacks.

Rahimullah Yusufzai, executive editor of Pakistan's English-language periodical The News, said Mehsud stood short in stature, but earned the respect of his fighters because of his militant past.

"He made his name because he had fought in Afghanistan against the Soviet occupying forces and then against the Americans," he told Â鶹´«Ã½ Channel in a phone interview from Peshawar, Pakistan on Friday morning. "That's why he became very popular among the militants and he became the leader."

Mehsud had threatened to attack Washington, though there is no record of him launching successful attacks in the West.

In a rare event, Mehsud held a press conference last year stating his intention to become a martyr, and explaining why the Taliban used suicide bombing as a response to American bombs.

"America is bombing us and we are facing cruelty, so we will support these suicide attacks," he said. "They (suicide bombers) are our atom bombs. Although the infidels have the atom bomb, our atom bombs are the finest in the world."

The U.S. had put a $5 million bounty on the Taliban leader's head, prior to his death.

But Pakistani authorities say that Mehsud's death does not end the Taliban threat.

Intelligence officials told AP that Taliban commanders have already begun the process of selecting Mehsud's replacement.

Three Pakistani officials put Mehsud's deputy, Hakim Ullah, at the top of the list to replace him.

Pakistani authorities, however, say they will not stop in their efforts to wipe out Mehsud's organization.

"It is a targeted law enforcement action against Baitullah Mehsud's group and it will continue till Baitullah Mehsud's group is eliminated forever," said Pakistani Interior Minister Rehman Malik.

With files from The Associated Press