The release of Pakistan's envoy to Afghanistan was part of a deal between the government and the local Taliban, under which they will swap about 330 prisoners after signing a formal peace agreement in the restive northwest tribal areas, a militant spokesman has said.

Maulvi Omar, the spokesman for Pakistani Taliban commander Baitullah Mehsud, said on Sunday that the release of Pakistani ambassador to Afghanistan Tariq Azizuddin was part of the expected deal.

Azizuddin was handed over by militants to authorities at Razmak in North Waziristan on Friday evening, three months after he was kidnapped from the tribal areas. However, Rehman Malik, advisor to the Prime Minister on Interior Affairs, had said that no deal had been struck for the envoy's release.

Omar told the Dawn newspaper by telephone from the Bajaur tribal region that the Taliban wanted 250 militants, currently in the government's custody, to be swapped with 80 soldiers and government officials, who had been taken hostage by the rebels.

The two sides will exchange the prisoners after signing the peace deal, he said. Talks between the government and the Taliban are in progress and the former released over 50 militants in exchange for 18 security personnel last week.

Despite the peace talks, the Taliban on Sunday carried out a suicide bombing in the cantonment of Mardan city in the North West Frontier Province on Sunday night, killing 13 people, including four soldiers.

A Taliban spokesman said that the attack was carried out in retaliation to military operations in Darra Adam Khel town of the NWFP.

Meanwhile, Taliban militants occupied the house of parliamentarian Shaukatullah Khan in the Bajaur tribal region on Sunday and held members of his family hostage for several hours. Khan was away when over 40 militants besieged his house.

The incident triggered panic in the area and the issue was resolved after the political administration sent elders to mediate with the Taliban. The militants left Khan's home on the condition that he would support their cause and hand over some marble mines in the area to a local tribe.

Taiban spokesman Maulvi Omar claimed that the incident was caused by a misunderstanding between his associates and Khan's family.