Elsewhere in the south, security forces killed at least one suspected Taleban and seized 20 others in a sweep through a known rebel hotbed, the interior ministry said.

The suicide blast, the latest in a raft of such attacks in Afghanistan, rocked the small provincial capital of Farah in the country’s far west, a relatively quiet area that is seeing an increase in militant violence.

A suspected suicide bomber detonated an explosives-filled car while being chased by police through the city centre, provincial governor Isatullah Wasifi told AFP.

The intended target of the suicide bomb was not certain although the bomb exploded near a NATO peacekeepers’ base and governor’s office.

Wasifi said a 22-year-old man wearing a burqa, the all-covering garment worn by some Afghan women, was detained near the site of the blast on suspicion of helping the attacker detonate the explosives.

The Afghan army was meanwhile planning an assault on a district in the southern province of Uruzgan that had been in Taleban control for more than 24 hours after being stormed by the rebels late Tuesday, an army general said.

The strike on Chora district was being planned with coalition forces and police, said General Rahmatullah Raufi, military commander for southern Afghanistan.

“The district is out of our hands,” the general said.

A small deployment of police in the remote district resisted the Taleban assault, which some officials said was launched by ”hundreds” of rebels, but fled after a few hours.

The Taleban movement, trying to regain control of the government that it lost in a US-led operation in 2001, often claims to hold districts in the south where they are most active.

This is the first time however that a government official has admitted they have been in control of an area for more than a few hours.

The interior ministry announced meanwhile that troops had clashed with rebels during a sweep of the southern province of Zabul Wednesday, with one militant killed in a three-hour gunfight.