At least one civilian died after a bomb exploded Sunday near a convoy carrying the mayor of Kandahar city, who escaped with slight injuries. Two others were wounded.
Initial reports suggest the bomb may have been transported by bicycle.
Meanwhile, there were more than a dozen deaths across Afghanistan in several other incidents that highlight the rise of violence in spring fighting.
The U.S. military reported killing five militants while conducting a raid in Kandahar's Maywand district with Afghan special forces. The raid was directed at a network that supported foreign fighters in the area.
In a separate incident, four Jalalabad-based U.S. soldiers were killed in eastern Afghanistan in a roadside bomb attack. The incident happened near the Afghan-Pakistan border.
The military alliance said two of the soldiers died after the blast, while two others succumbed to their wounds later on.
In Kabul, a suicide bomber on foot killed an unknown number of Afghan civilians, said Lt. Gen. Abdul Rahman Rahman. At least 14 other civilians were injured.
The bomber had been targeting a NATO patrol, but no foreign troops were wounded or killed, the Interior Ministry said in a statement.
Coalition troops have been battling insurgents in Afghanistan since the conflict began in 2001 and the mission has become increasingly more deadly.
With files from The Associated Press
