Islamabad, March 1: Two people were killed and 20 injured in a suicide attack at a security convoy in north-west Pakistan Saturday, as the police launched a probe into the bombing that left 42 people dead during a funeral Friday, officials said.

The suicide bomber rammed his explosives-laden vehicle into two paramilitary vehicles travelling near Khar, the main town in Bajaur tribal district that borders Afghanistan.

A security official was killed, while the torched body of the suicide bomber has also been recovered from the vehicle, said local government official Iqbal Khattak. Nine law enforcement officers and 11 civilians were also injured in the attack.

Pakistan's tribal areas are believed to have safe-havens of Al Qaeda militants and Taliban fighters who launch cross-border attacks on international forces into Afghanistan.

The blast came a day after a suicide attack at a Muslim funeral prayer for Javed Iqbal, a deputy police superintendent, left 42 people dead and 81 injured in Mangora, a town in the restive Swat Valley of the neighbouring North West Frontier Province. Iqbal was killed Friday morning in a roadside bomb attack.

No one has claimed responsibility for the suicide attack. But local officials believe it was carried out by the followers of pro-Taliban cleric Maulana Fazlullah, who is thought to be behind dozens of suicide bombings in the scenic valley since October 2007 when the Pakistani Army was sent to the area to flush out Islamic militants.

"The security forces have cleared much of the area of the insurgents but some of them are still hiding in the mountains from where they conduct such heinous actions," district police officer Waqif Khan said.

Hundreds of mourners were assembled in Mangora town Saturday morning to attend the joint funeral for several of the victims.