US military bases have come under concentrated rocket attacks in Iraq.
In what seems to be the most serious raid on American forces since May 2009, six rockets have been fired into a base in the southern city of Nassiriya.
On Friday, another US military base was attacked in the northeastern city of Baqouba.
It is believed around five US service personnel may have been been killed in attacks on Camp Victory on the outskirts of Baghdad in an attack last week.
There are currently about 50,000 US soldiers in Iraq, mainly involved in training operations.
They are due to leave the country by the end of this year in line with the 2008 US-Iraq Status of Forces Agreement.