Afghan car bomb attack kills 21

The bombing happened in Kandahar province where four Nato soldiers were also killed on Thursday in separate attacks by suspected Taleban fighters.

Earlier this week, UK and Canadian-led Nato forces took control of military operations in southern Afghanistan from US-led coalition troops.

The area has become a stronghold of the Taleban.

Hundreds of people have been killed there in fighting in recent months.

Thursday saw one of the bloodiest days in Kandahar since the end of the war, the BBC's Alastair Leithead in Afghanistan said.

A suicide car bomber detonated his explosives in a crowded market in Panjwayi town, local officials said.

Civilians were deliberately targeted in the attack, which claimed the lives of children, the Afghan interior ministry said.

The blast left a 1.5m-wide (5ft) crater and scorched several shops. Bloodied caps and shoes lay in the road, the Associated Press (AP) news agency reports.

A convoy of Nato troops was moving through the area when the attack took place, but was unaffected, an alliance spokesman said.

"They were close enough to hear the blast," the spokesman, Maj Scott Lundy, told the AP.

Rising Nato death toll

Three Canadian soldiers with Nato were killed in a rocket-propelled grenade attack on the outskirts of Kandahar city. Six other soldiers were wounded.

The rockets were fired from a school near the village of Pashmul, Nato said.

Earlier, another Canadian soldier was killed also near Kandahar city and four others were injured in two separate roadside bombs targeting at military patrols.

And local officials said 10 Taleban fighters were killed by Afghan and Nato forces in the neighbouring Helmand province, during a raid on a Taleban hideout.

Seven Nato soldiers - three of them British - have now been killed since the alliance assumed control of operations in the south on Monday in the first land deployment outside Europe for Nato forces.

The 8,000 soldiers are under the umbrella of Nato's International Security Assistance Force (Isaf) in six provinces in the south: Day Kundi, Helmand, Kandahar, Nimroz, Uruzgan and Zabul.