An Afghan police official says it is thought that about a dozen Nepalese security guards were killed when a suicide bomber targeted their minibus in an attack in the Afghan capital Kabul.

The official, who did not want to give his name as was not authorized to speak to the media, said and exact figure was not possible because of the confusion surrounding the blast. He says seven others were thought to be hurt the Monday morning attack.

Dozens of police and many ambulances rushed to the scene to take the victims to hospitals.

No group has claimed responsibility for the attack, but Taliban insurgents have increased attacks on both government employees and Afghan security forces across the country.