An army complex that hosts U.S. forces next to Baghdad International Airport was hit by several rockets on December 9, wounding six Iraqi troops, the military said in a statement.
Security sources said the wounded are members of Iraq's Counter-Terrorism Service, an elite unit that was established and trained by U.S. forces. Two of them are in critical condition, the sources said.
The complex also hosts a small group of U.S. soldiers and diplomats.
Launchers with rockets that had not been fired properly were left in the area, indicating that a larger attack had been planned, the statement said.
It is the latest in a series of rocket attacks targeting either Iraqi bases where U.S. forces are stationed or the American Embassy in Baghdad.
There have been at least nine attacks against U.S. targets in Iraq in the past six weeks.
No one has claimed responsibility and no U.S. forces have been wounded.
Security sources have linked at least one attack to Kataib Hizballah, a Shi'ite militia with close ties to Iran and blacklisted by Washington.