"Our mission in Islamabad in Pakistan, which is also accredited in Afghanistan, has informed us that eight South Africans were among the dead in the explosion which occurred in Kabul early this morning," foreign affairs spokesman Nelson Kgwete told AFP.

They worked for a private aviation company," he added.

The group were all believed to be men, Kgwete said.

"Our mission in Islamabad is working on the identity of the men and contacting their next of kin."

Tuesday's attack by a woman suicide bomber was the deadliest single attack claimed to avenge a US film that has sparked a week of bloody protests across the Muslim world.

More than 30 people have now been killed in the violent backlash over a YouTube trailer for the film "Innocence of Muslims".

A suicide car bomber struck a van carrying airline pilots to Kabul airport early on Tuesday, killing nine Russian and South African nationals and one Afghan, officials said.

  “According to our latest figures, nine Russians and South Africans including a woman with their Afghan driver were killed in today suicide bombing,” Mohammad Daud Amin, Kabul deputy police chief said.

  The victims were travelling in a van in a road connecting to the Kabul airport on Tuesday morning’s rush hour when the suicide bomber rammed an explosive-laden vehicle into the van.

  Amin said 14 others, mostly civilians, were wounded in the bombing near a petrol station north of Kabul city.

  “The victims who were heading off toward the airport, were employees of ACS, an aerial transporter company,” he said.

  But a spokesman for Russian embassy in Kabul said seven South Africans, one Kirghiz, an Afghan interpreter and the driver were killed.

  “What we know is that there were no Russian nationals involved,” Stepan Anikejew said, adding that the British-based company provides services to the US embassy in Kabul.

  US officials in Kabul confirmed that the victims were employees of a private company contracted by the embassy.

  Insurgent group Hezb-e-Islami, led by Gulbuddin Hekmatyar, claimed responsibility for the attack.

  The attack was a response to an internet film mocking the Prophet Mohammed that sparked violent protests around the world, rebel spokesman Zubair Seddiqi said.

  “The bombing was carried out by Fatima, a 20-year-old girl, who was a Kabul resident to retaliate for the anti-Islam movie,” he said, claiming that 16 Americans were killed.

  Kabul police could not verify the gender of the bomber.