A suicide bomber has blown himself up next to a vehicle carrying U.S. nationals near the Afghan capital, Kabul, wounding four people, including two Americans.

Local authorities say the attacker, with explosives strapped to his body, ran in front of the vehicle Sunday before blowing himself up.  One report said the vehicle was carrying U.S. engineers, but another said the wounded were U.S. soldiers.

Hours earlier, in the southern city of Kandahar, another suicide bomber set off his explosives near a convoy of Canadian troops, killing himself and a civilian.  The explosion hurt five passersby, and slightly wounded three soldiers with the NATO-led force. 

The suicide bombings came as NATO and Afghan forces announced the combat phase of an anti-Taleban offensive in the south has been completed successfully and reconstruction work will begin soon.  They said more than 500 insurgents were killed in the two-week operation to drive Taleban forces from the area.

In eastern Afghanistan, American and Afghan troops launched a new offensive against Taleban insurgents.  U.S military officials say seven-thousand soldiers are involved in the "Operation Mountain Fury" in five eastern provinces.

On Saturday, the commander of NATO forces in Afghanistan (Lieutenant General David Richards) told British television he expects the military campaign against the Taleban to last another three to five years.

 Some information for this report provided by Reuters, AP and AFP.