At least three people were killed, including two US soldiers, and 10 wounded after rockets were fired at the Taji Camp in Iraq that houses international forces.
US officials quoted by media said on Wednesday that another of the dead was a British national.
The rocket attack was the 22nd against American military interests in the country since late October, an Iraqi military commander said.
US Army Colonel Myles Caggins, a US military spokesman in Iraq, said on Twitter more than 15 small rockets hit the base but provided no further details.
One American official, speaking to The Associated Press on condition of anonymity, said more information would be given later in an official announcement.
You can read more from our friends at Al-Jazeera