Two Afghan intelligence agents and three civilian were killed by a suicide bomber in eastern Afghanistan, while more than 15 Taliban militants were killed by Afghan police and a NATO airstrike in the southern region, official sources revealed.

The bomber detonated his explosive-packed vest in the main market in Zazi Maidan district of south-eastern province of Khost, Arsala Jamal, provincial governor told Deutsche Presse-Agentur dpa.

"All five dead men were civilians. They were local shopkeepers," Jamal said, adding the site of the attack was close to the main police headquarters in the district and an intelligence office.

However, Mohammad Younuz Zadran, district chief of the Zazi Maidan, said that the attack was against a former militia commander, who had helped coalition forces in their fight against Taliban militants in the area soon after the fall of the Taliban government.

He said two of the dead men were intelligence officers. Zadran had earlier said that the two dead men were police officers.

Both officials blamed Taliban insurgents for the attack. The militants, who lost power in late 2001, have begun to rely heavily on use of suicide and roadside attacks, both tactics are widely believed to have been copied from Iraqi insurgents.

The Taliban took responsibility for the attack in a statement posted at their website, saying they killed 20 intelligence officials in the attack, which was carried out by one of their fighters, named Rasoul Mohammad.

Meanwhile, more than 15 Taliban militants were killed after they attacked a convoy, carrying logistics for NATO forces in Zherai district of southern Kandahar province on Friday morning, General Rahmatuallh Raoufi, provincial governor told dpa.

"Local police rushed to the scene and fought with the attackers, while NATO planes bombed from air," Raoufi said, adding, "More than 15 Taliban militants were killed by the ground and air forces."

The governor said that one oil tanker in the convoy was burned, but there were no other casualties among the police forces or convoy's security guards.

Taliban militants are mostly entrenched in eastern and southern regions of the country, which lie along the border with Pakistan, and where Afghan officials claim that Taliban militants have sanctuaries.

More than 4,000 people - mostly insurgents - have been killed in Afghanistan's conflict so far this year.