The United Nations says the Afghan Government is to provide armed escorts for UN staff travelling on roads in the south of the country.
The announcement follows a string of attacks on UN mine-clearance workers, which have been blamed by Afghan officials on remnants of the ousted Taleban regime.
The latest attack was reported a couple of hours before the UN announcement.
Unidentified gunmen opened fire on a UN vehicle on the main road between the eastern towns of Gardez and Khost.
Two Afghan mine-clearance staff were injured.
From the newsroom of the BBC World Service