At least four US soldiers were wounded in a rocket attack that targeted a US military base just outside Baghdad.
Major Philip Smith of the 1st Cavalry Division confirmed the toll and said the explosion damaged a military vehicle as well as the "forward operating base".
A second car bomb attack hit a government compound near the Abu Ghraib commissioner headquarters - which houses the district police station.
Sources told Aljazeera that at least seven people were injured and that a US tank guarding the station was badly damaged.
Mosul police killed
Meanwhile, unknown assailants killed two Iraqi policemen in Mosul, Iraq's third largest city in the north of the country.
Major Ghassan Salih and Colonel Muzahim Shummari died when a car they were travelling in was strafed with bullets.
Some 370km north of Baghdad, Mosul has been repeatedly rocked by attacks on police, officials and professionals linked to the US presence in Iraq.
A car bomb exploded late on Tuesday there as a US convoy travelled near the University of Mosul, wounding six US soldiers.
Two Iraqi security guards were also wounded in the attack.