The U.S. military in Iraq says a mortar attack on a base near Baghdad International Airport has wounded 11 soldiers.
A spokesman said at least 10 mortar rounds hit the logistics base early Wednesday, triggering a fire that burned for more than an hour.
In another incident, a bomb exploded in the town of Samawa, about 270 kilometers south of Baghdad, where Japanese troops are deployed.
Local officials said the blast site was not near the Japanese military camp. They said two Iraqis - one policeman and a civilian - were slightly injured.
U.S. and Iraqi authorities have warned that Monday's transfer of sovereignty would not immediately halt insurgents attacks.