The attack is the latest targeting international troops, but there is no immediate word on casualties.
Local government spokesman Mubarez Zadran says a suicide car bomber struck the convoy as it rolled through Khost province's Mando Zayi district. He says foreign troops quickly cordoned off the road.
A spokeswoman for the international force, Lt Cmdr Katie Kendrick, confirmed the Khost explosion, but said the convoy apparently hit a roadside bomb. She said no casualties were immediately reported.
Insurgents have intensified attacks as 30,000 more American troops arrive to try to turn around the 9-year-old war and stabilise the Afghan government.(AP
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