No terrorist group has claimed responsibility for the attack yet.
An explosion has taken place close to Kandahar city in South of Afghanistan amid reports a vehicles convoy of the security forces are targeted. The insurgents routinely exaggerate their gains and casualties they inflict in battle.
Kandahar province was the Taliban spiritual and leadership headquarters during their five-year rule that ended in with the USA invasion in 2001.
He said that the convoy near a base of the Afghan spy agency National Directorate of Security had been attacked.
Casualties were reported, but Resolute Support did not provide information about the number or type.
"At around noon a vehicle bomb targeted a convoy of foreign forces in Daman area of Kandahar", said provincial police spokesman Zia Durrani.
The combined US and North Atlantic Treaty Organisation troop contingent now in Afghanistan is about 13,500.
On Tuesday two suicide bombers had killed at least 29 and wounded more than 64 people at a Shiite mosque in Herat province of Afghanistan during evening prayers.