DERA ISMAIL KHAN: Fierce clashes between Taliban fighters and those loyal to a pro-government warlord killed at least 70 people Wednesday, intelligence officials said, a week after a CIA drone reportedly killed the top Taliban leader in Pakistan.

The battles pitched Taliban militants against followers of tribal warlord Turkistan Bitani on the fringes of the South Waziristan border region, where U.S. and Pakistani officials believe Taliban chief Baitullah Mehsud died in a missile strike on Aug. 5.

Pakistan's army sent in helicopter gunships as reinforcements to pound about 300 Taliban fighters attacking Bitani's mountain stronghold, two intelligence officials said. They spoke on condition of anonymity because they were not authorized to talk to the media.

The fighting raged for five hours, with militants using rockets, mortars and anti-aircraft guns against Bitani's village of Sura Ghar, the officials said. They said wireless intercepts from the area showed at least 70 people including one woman in the village were killed. Ten of the dead were from Bitani's stronghold, the officials said, while the rest were militants.

It was impossible to independently confirm the death toll, as the fighting was taking place in a remote mountainous area that is off-limits to journalists.

Bitani put the casualty figure higher, telling The Associated Press that about 90 fighters were killed and 40 houses destroyed.

The fighting followed days of confusion and competing claims over Mehsud's fate. While U.S. and Pakistani officials say they are almost certain he is dead, Taliban commanders insist he is alive.

Neither side has produced any evidence, 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 missile strike, Interior Minister Rehman Malik claimed a Taliban meeting to choose Mehsud's successor degenerated into a gunbattle between the leading contenders — 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 survived.

Baitullah Mehsud and his followers have been the target of both U.S. and Pakistani operations aimed at ridding the country's volatile 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 (100 kilometers) 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 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.

Separately, a bomb and gunfire attack against a paramilitary checkpoint in the southwestern city of Quetta killed at least two passers-by and wounded four other people, including a police officer, authorities said.

Senior police officer Mohammad Suleman said a booby-trapped motorcycle exploded near a Frontier Corps checkpoint, and then gunmen on another motorcycle opened fire.

Quetta is the capital of Baluchistan, where ethnic Baluch militants have waged a low-level insurgency for decades. Suleman said Baluch separatists were suspected in the attack.