KANDAHAR, Afghanistan, April 1, 2008 (AFP) - New Taliban-linked violence left eight people dead in Afghanistan as President Hamid Karzai headed Tuesday to a NATO summit to call for more help in fighting the deadly unrest, officials said.

The latest bloodshed was in the south, where Taliban are said to be tied into the opium and heroin trade and where commanders in NATO's International Security Assistance Force (ISAF) say they need more troops and resources.

A suicide attacker blew up a car bomb inside a district police compound in the southwestern province of Nimroz. Two policemen were killed and five wounded, provincial deputy police chief Assadullah Sherzad told AFP.

Police had brought the bomb-filled car into the compound in Khash Rod district to do 'the usual paper work' after it had had an accident with a police vehicle, he said.

'As they entered, the driver detonated his car bomb,' he said. It was not clear if the bomber had intentionally collided with police.

There was no immediate claim of responsibility for the attack, but it was similar to scores carried out by Taliban.

Provincial governor Ghulam Dastageer Azad told AFP the policemen involved in the initial car accident had been working in campaigns to destroy illegal opium poppy fields.

Afghanistan makes more than 90 percent of the world's illegal opium, which is used to make heroin. Officials say Taliban earn money from the lucrative trade by protecting farmers and smuggling routes.

Police in neighbouring Helmand province announced meanwhile that a mid-level Taliban commander who twice escaped from Afghan jails was recaptured following a clash Monday that left three of his fighters dead.

Mullah Naqibullah's men had been wearing police uniforms when they attacked a police patrol, provincial police chief Mohammad Hussein Andiwal said.

And in adjoining Kandahar province an ISAF strike killed three men late Monday that the alliance force said were insurgents laying mines, but a government official said they were farmers watering their crops.

About 70,000 international soldiers -- with ISAF and a separate US-led coalition -- are fighting the insurgency alongside Afghan security forces.

The violence started after the Taliban were ousted from government in late 2001 for harbouring Al-Qaeda leaders and was its deadliest last year, with about 8,000 dead -- mostly rebels.

Karzai left for NATO's Bucharest summit with his defence and foreign ministers, and a message that Afghanistan lacks the capacity 'to effectively fight terrorism,' his office said.

He would also tell a special session on Afghanistan Thursday that the Afghan National Army should take greater responsibility for security in Kabul and other major cities and touch on the NATO strategy here, it said.

US Defence Secretary Robert Gates said in Denmark he was 'reasonably optimistic' NATO would send reinforcements to southern Afghanistan but they would not be 'anywhere near' what had been asked for.

ISAF commander, US General Dan McNeil, has requested two combat brigades and a brigade of trainers -- about 10,000 troops.

France is expected at the summit to pledge extra soldiers, which Prime Minister Francois Fillon said Tuesday could number 'several hundred'.