A homicide car bomber attacked a convoy carrying foreigners near the Afghan capital Saturday, wounding two foreigners and four Afghans, officials said.

The attack occurred on a main road leading out of Kabul and left one vehicle in flames, said Ali Shah Paktaiwal, chief of criminal investigations in Kabul.

"The attacker detonated himself near a convoy carrying foreigners," he said, adding it was not clear whether it was a military or civilian convoy.

Zemerai Bashary, a spokesman for the interior ministry, said two foreigners and four Afghans were wounded in the attack. He said he did not know the extent of their injuries, or the nationality of the foreigners.

Insurgent violence in Afghanistan is running at its highest level since U.S. forces invaded the country in 2001 to oust the hard-line Islamic Taliban rulers, who had harbored Al Qaeda leaders following the attacks on the United States on Sept. 11, 2001.

Most of the bloodshed has taken place in southern or eastern Afghanistan where the Taliban have historically been strongest, but there have been occasional homicide attacks on Afghan security forces and Western targets in Kabul.

Elsewhere Saturday, insurgents detonated a roadside bomb that killed two Afghans guarding a convoy carrying supplies for NATO-led forces in southern Kandahar province, said provincial police chief Sayed Aqa Saqib.

In neighboring Helmand province, Afghan soldiers shot and killed two suspected Taliban fighters as they attempted to plant a roadside bomb, said police officer Ghulam Wali. The bomb was later defused, he said.

On Friday, insurgents attacked a police patrol in eastern Paktika, sparking a gunbattle that killed six militants and one officer, the interior ministry said in a statement. It gave no more details.