The United States military in Iraq says two soldiers have been killed and about 40 people wounded in a rocket or mortar attack on Baghdad's main US base.
Camp Victory is the headquarters of the US military in Baghdad
A statement described the two soldiers as members of the coalition forces but did not give further details.
The attack happened on Wednesday at the sprawling base known as Camp Victory, home of the US military HQ in Iraq.
Camp Victory and other US bases often come under fire, but attacks with such a large number of casualties are rare.
The US military also said two "third country nationals" were wounded, a term usually used for non-Iraqi, non-US contractors in Iraq.
Most of the troops stationed at Camp Victory are American.
In September, one person was killed and 11 were wounded when Camp Victory was attacked with what the US military said was a 240mm rocket supplied by Iran to Shia extremists.