At least 50 people have been killed in a suicide bombing at a mosque in northwest Pakistan, apparently targeting Aftab Khan Sherpao, the country's former interior minister.

Police on Friday said the bomber blew himself up while worshippers were offering Eid prayers, detonating himself in the row behind the former minister.

Sherpao was safe, but one of his sons was injured, local authorities said.

"Yes, I'm fine," Sherpao told The Associated Press.

The blast went off in Sherpao's residential compound in a village about 40km northeast of the city of Peshawar.

Feroz Shah, police chief for Charsadda district, said: "At least 50 people have been killed and dozens were injured in the attack. I fear the death toll may rise further."

"The bomber was among the people, who were offering Eid prayers," Muhammad Sharif Virk, a senior police official said. "He was standing in the second row behind the former interior minister."

'Doomsday'

Shaukat Ali, 26, who survived the blast, said: "We were saying prayers when this huge explosion occurred."

"It almost blew out our ear drums. Then it was it was like a scene from Doomsday," he said. His white cloak and pants were torn and spattered with blood.

Dozens of wounded were taken to the hospital in Peshawar, the capital of Pakistan's North West Frontier Province.

The hospital was chaotic as injured arrived in pickup trucks, ambulance sirens wailed and wounded screamed for help.

It was the second suicide attack that apparently targeted Sherpao in eight months.

Kamal Hyder, Al Jazeera's correspondent in Pakistan, said: "It was widely expected that there would be more attacks against Aftab Khan Sherpao because of his close association with President [Pervez] Musharraf [and] with the so-called war on terror."

Sherpao belonged to Musharraf's government, which was disbanded ahead of January elections.

Hyder said: "Many people hold him personally responsible for what happened in the Red Mosque because Aftab Khan Sherpao was indeed the interior minister of the country when that happened."

"He had been warned there would be revenge attacks," Hyder said.

Friday's blast comes amid a surge in violence since security forces launched an assault on the Islamabad mosque in July, which had become a refuge for hardline religious students.

More than 800 people have died in the ensuing reprisal attacks across the country, with about half of them killed in suicide bombings.

Musharraf, a key ally in the US-led "war on terrorism", cited growing lawlessness as a main reason behind imposing emergency rule on November 3. He lifted emergency rule on December 15.

PHOTO CAPTION

Pakistani security officials search the scene of a bombing 21/12/07