A suicide car bomb attack outside a university in southern Afghanistan on Monday killed at least seven civilians and wounded more than 20, officials said.

The attack happened around 7:00 pm (1430 GMT) in Kandahar city in front of Kandahar University, around two kilometres (a mile) from a major US military base, provincial police chief General Abdul Razaq told AFP.

"This evening a suicide car bomb exploded near Kandahar university, killing seven civilians and wounding 23 others." he said.

The provincial governor's spokesman Jawed Faisal confirmed the death toll and said most of the victims were Afghans working at the US base, which was once the compound of Taliban leader Mullah Omar.

"A Toyota Corolla packed with explosives rammed into a minivan full of workers coming from the base," Faisal told AFP.

Kandahar was the birthplace of the extremist Taliban regime which ruled Afghanistan from 1996 until it was deposed by a US-led invasion in 2001.

It remains one of the hotbeds of the decade-long insurgency against the Western-backed government of President Hamid Karzai.

NATO and Afghan forces are the main targets for the militants, whose tactics frequently include suicide attacks, but local civilians working for the coalition are also targeted.

Two weeks ago Taliban attackers stormed two Afghan-NATO bases in Kandahar province, killing four police officers.

The bulk of NATO's 130,000 troops in Afghanistan are due leave by the end of 2014, handing security responsibilities over to local forces, and there have been concerns the pullout may lead to a return to the chaotic violence of the 1990s.