Up to eight gunmen opened fire on a United Nations two-car convoy as it travelled in southeastern Afghanistan, but there were no injuries, a spokesman for the organisation said Sunday.

The UN's David Singh told reporters that one of the vehicles, an unmarked rental car carrying two government workers and an Afghan World Food Programme (WFP) employee was riddled with bullets in the attack Friday.

UN road movements have been suspended following the incident on the route between Wazakhan and Khairkot in Paktika province, Singh said.

While the gunmen hijacked the unmarked car, the WFP vehicle following it turned back to fetch help.

"They returned to the scene of the incident with local authorities, they found the three passengers unharmed by the side of the road," Singh said.