In a daring attack, a suicide bomber on Sunday blew himself up at a gathering of tribal elders, killing at least 22 people at Darra Adam Khel in northwestern Pakistan.

Most of the dead were tribal elders. Two politicians who contested the February 18 general election were also killed, witnesses said.

The jirga or coucil meeting, which was being attended by elders of five prominent tribes and local politicians, had been convened to discuss the security situation and steps to restore peace in Darra Adam Khel, which has witnessed a spurt in the activities of pro-Taliban militants in the past few months.

Local residents said the suicide attacker managed to enter the jirga and blew himself up. No group claimed responsibility for the bombing that sparked tension in the region.

Such attacks are usually blamed by the government on pro-Taliban militants operating in the NWFP and nearby tribal areas bordering Afghanistan.

Pakistan army soldiers cordoned off the site of the blast and began patrolling the area, including the nearby strategic Indus Highway.

Personnel of the local Khasadar militia and levy force also reached the spot and help transport the injured to hospitals in Darra Adam Khel and nearby Kohat.

The seriously injured persons were taken to the North West Frontier Province capital of Peshawar.

The elders of tribes living in the Darra Adam Khel area had recently said they would not allow any militants or foreign fighters to operate in their area.

They had also warned that the house of any person found sheltering militants or foreigners would be burnt down in keeping with tribal traditions.

The NWFP has witnessed some of the most deadly suicide attacks in the past few months.

On Friday, nearly 50 people were killed at Mingora town in the province when a suicide bomber blew himself up amidst hundreds of mourners attending the funeral of a police officer slain by militants.

The government has stepped up security across the country in the wake of Sunday's suicide attack.

Security was also stepped up for top political personalities, including PPP co-chairman Asif Ali Zardari, Pakistan Muslim League-Q leader and former minister Sheikh Rashid Ahmed and Jamiat Ulema-e-Islam leader Maulana Fazlur Rehman.