At least four American soldiers were killed and seven wounded before dawn Saturday when two rockets hit a U.S. base north of Baghdad, U.S. military officials said. Two 57-mm rockets slammed into the base in Taji at 5:30 a.m., said Air Force Lt. Col. Sam Hudspath, The AP reported. Earlier on Saturday, a car bomb went off near the main U.S. base in the northern city of Tikrit, a U.S. official said. At least three people were killed. Unidentified car driver appeared to be driving the car when it detonated outside the outer wall of the base, said Master Sgt. Robert Powell of the 1st Infantry Division. The car exploded near a row of shops outside the base. Witnesses said the blast was targeting a convoy of Iraqi officials heading to the Mayor's office in Tikrit. **PHOTO CAPTION*** Iraqi's gather around burned out cars following an overnight shooting incident between al-Mahdai army, supporters of the Shiite cleric Moqtada al-Sadr and U.S. troops in the Baghdad suburb of Al Sadr CityI, Iraq, Saturday, 24 April 2004. (AP)