A roadside bomb tore through a police vehicle in an insurgent attack in a southern Afghanistan flashpoint on Saturday, killing seven officers, the interior ministry said.

The incident took place in Registan district in Kandahar province, a hotbed for the Taliban-led insurgency, the ministry said.

"A roadside bomb struck a police vehicle which resulted in the martyrdom of seven policemen," the statement said. Two other officers were wounded in the blast, which the ministry blamed on insurgents.

In the north, a bomb blast killed an Afghan civilian and wounded another in the province of Jawzjan, the ministry said.

The Taliban insurgency, now at its deadliest since the 2001 US-led invasion, is concentrated in southern and eastern Afghanistan but has also affected some parts of the previously peaceful north.

About 4,000 US marines along with 600 Afghan forces have launched a massive operation against rebel hideouts in Helmand, the economic engine of the Taliban insurgency in southern Afghanistan, on the Pakistani border.