There is a strong likelihood that Pakistani Taliban chief Baitullah Mehsud was killed along with his wife and bodyguards in a missile attack two days ago, Pakistan's Interior Minister Rehman Malik told Reuters.
"We suspect he was killed in the missile strike," Malik said on Friday. "We have some information, but we don't have material evidence to confirm it."
ABC News cited a senior US official as saying there was a 95 per cent chance that Mehsud was among those killed in the missile strike. US officials have visual and other indicators it was Mehsud and Pakistanis are now trying to collect physical evidence to be certain, ABC reported.
A US official also told Reuters that there was reason to believe Mehsud was dead.
"There is reason to believe that reports of his death may be true, but it can't be confirmed at this time," said the official, providing the information on condition of anonymity.
The official would not comment on the circumstances surrounding Mehsud's possible death.
The United States has placed a $5 million reward on the head of Mehsud, an ally of al-Qaeda widely regarded in Pakistan as Public Enemy No 1.
The attack in a tribal region of northwest Pakistan was believed to have been carried out by a pilotless US drone aircraft at around 1:00 am on Wednesday.
Neither the Pakistani nor US governments confirm such attacks because of sensitivities over violation of Pakistan's territorial sovereignty.
Intelligence officials and relatives had confirmed earlier that Mehsud's second wife had been killed in the missile strike that targeted her father's home in an outlying settlement close to Makeen village in the South Waziristan tribal region.
A relative of Mehsud's dead wife had initially said the Taliban leader wasn't present when the missiles struck, but rumours that he had either been wounded or killed refused to die down.
The stricken house is some two hours' walk from Makeen, and Taliban fighters had cordoned off the area, refusing to let people enter, according to villagers.
A senior Pakistani security official said that aside from Mehsud's wife, one of Mehsud's brothers and seven of his bodyguards perished in the attack.
The official said intelligence services were trying to discover the identity of another victim, and there was a good chance it was Mehsud.
Intelligence agents had also picked up signs that leaders of various Taliban factions planned to gather for a shura, or council meeting, somewhere in Waziristan later on Friday.
Sometimes in the past, militant leaders presumed to have been killed have resurfaced later.
Mehsud declared himself leader of the Pakistan Taliban, grouping around 13 factions in the northwest, in late 2007, and his fighters have been behind a wave of suicide attacks inside Pakistan and on Western forces across the border in Afghanistan.
He is accused of being behind the assassination of Benazir Bhutto in December 2007, a charge he has denied. Conspiracy theories abound over who killed the former prime minister.
US missile attacks on Mehsud territory in South Waziristan became more frequent after the Pakistan government ordered a military offensive against him in June.
Pakistan forces have also bombarded Mehsud's stronghold with air raids and artillery.
Mehsud is estimated to have between 10,000 and over 20,000 battle-hardened fighters with him in the mountains.
The army has sealed roads around Mehsud's territory and villagers have fled the area, but as the days have dragged on there was growing speculation that the strategy might be to isolate him by stealth rather than launch a full-blown assault.