A bomb blast at a mosque in the Khyber tribal area killed at least 30 people and wounded more than 70 others on Thursday, residents and security officials in the region said.

The blast struck a meeting of militants in the Aka Khel area of the Khyber tribal region, near the Afghan border. Local residents and security officials said a local militant commander, Azam Khan, was killed in the explosion. Mr. Khan, who ran the local FM radio station, was delivering a sermon on the radio when the blast occurred.

There were no claims of responsibility, and the blast appeared to be either an accident or a result of fighting among militants.

Mr. Khan was affiliated with Lashkar-e-Islam, a militant group commanded by Mangal Bagh. The Khyber district borders the Orakzai tribal region, and an intelligence official said some of the dead were affiliated with Maulvi Noor Jamal, a Pakistani Taliban commander in the tribal areas of Orakzai and Kurram.

One Pakistani intelligence official in Peshawar said the militants had been using the mosque as their headquarters and were preparing suicide vests and roadside bombs when one of the vests exploded. He said the death toll was so high because the mosque was near a market.

But other Pakistani officials said the blast might have been an attack and a result of a power struggle between Lashkar-e-Islam and Ansar ul-Islam, a rival militant group.

Both groups have clashed in their efforts to take control of Khyber, which is adjacent to the provincial capital, Peshawar.