Clashes between Taliban militants and a pro-government group in northwestern Pakistan's tribal belt on Wednesday have left at least 70 fighters dead, two intelligence officials and a militant commander said.

Turkistan Bitani, a tribal warlord allied with the government, claimed Taliban militants attacked his men in the Jandola area, just outside the stronghold of Taliban leader Baitulah Mehsid in South Waziristan.

Two Pakistani intelligence officials said they used rockets, mortars and anti-aircraft guns against Bitani's village of Sura Ghar. They confirmed at least 70 people were killed. The officials, who cited wireless intercepts from the site, spoke on condition of anonymity because they were not authorized to speak to the press.

Bitani told The Associated Press that 90 fighters were killed and said more than 40 houses had been destroyed. There was no way to independently confirm the death toll, as the fighting was taking place in a remote, mountainous area that is off-limits to journalists.

The clash comes one week after a U.S. missile strike in South Waziristan reportedly killed Mehsud. The U.S. and Pakistani officials say they are almost certain last Wednesday's strike killed the Taliban leader, but several Taliban fighters have disputed that, insisting Mehsud is alive.

Neither side has produced any evidence to back up their assertions, and since the claims of Mehsud's death, both the Taliban and the Pakistani government have been waging competing propaganda campaigns over the state of the Taliban's leadership.

Days after the strike, Interior Minister Rehman Malik claimed a Taliban meeting to chose Mehsud's successor degenerated into a gunbattle between leading contenders to replace Mehsud — Waliur Rehman and Hakimullah Mehsud — and that one of the two was dead.

Bitani made similar claims, saying there had been a gunfight at the meeting, known as a shura — although he had said both Rehman and Hakimullah Mehsud were dead.

The two militant commanders both later phoned international media organizations to prove they were alive.

Mehsud and his followers have been the target of both U.S. and Pakistani operations aimed at ridding the country's northwest of militants.

Washington has increased its focus on Pakistan's rugged tribal regions because they provide safe haven for insurgents fighting international forces across the border in Afghanistan. The U.S. is also concerned the militants could undermine the stability of the government in Islamabad, especially after Taliban insurgents briefly captured areas some 60 miles from the capital. That bold takeover stoked fears Pakistan's nuclear weapons could fall into the wrong hands.

A recent report written by a U.K.-based security expert said that militants had attacked nuclear facilities three times in two years, but a military spokesman denied that on Wednesday.

Maj. Gen. Athar Abbas said there is "absolutely no chance" the country's atomic weapons could fall into terrorist hands

Shaun Gregory, a professor at Bradford University's Pakistan Security Research Unit, wrote that several militant attacks have already hit military bases where nuclear components are secretly stored. The article appeared in the July newsletter of the Combating Terrorism Center of the U.S. Military Academy at West Point.

Abbas said Wednesday that none of the military bases named was used to store atomic weapons.