An Afghan official says three border policemen have been killed and three others were wounded in a suicide attack near an important border crossing in southern Afghanistan.

Zia Durrani, the police spokesman for Kandahar province, says the attack took place when five suicide bombers stormed the border police headquarters at Spin Boldak, on the border with Pakistan on Monday.

He says after the attackers entered the building, a firefight followed for about half an hour before the attackers detonated their explosives vests.

Spin Boldak links Kandahar to the Pakistani city of Quetta and is a major crossing between the two countries for people and goods.

No one immediately claimed responsibility for the attack.

Kandahar is the seat of the Taliban, who have waged war on the Kabul government since 2001.