Two US soldiers and two journalists were killed and 15 people wounded today in an Iraqi attack on a US communications centre on the southern outskirts of Baghdad, military sources said.
Two of those wounded were in critical condition, a US military official said. There were no further details.
"Some sort of a rocket hit near the 2nd Brigade's tactical operation centre south of the city," said Major Michael Birmingham, chief public affairs officer for the US 3rd Infantry.
In a separate incident in fighting on the eastern outskirts of Baghdad, two Marines were killed while trying to secure two bridges in what Marines said appeared to be an incident of "friendly fire".
Marines said two of their comrades were killed and three wounded by their own side when an artillery shell punched into their armoured vehicle.
"It was friendly fire. The artillery came in short," one said. "The Iraqis have been firing little artillery."
Colonel B. P. McCoy said the cause of the deaths was unclear, but he added that the Marines were investigating.
The incident on the eastern side of Baghdad occurred when the Marines were trying to secure two bridges over the Nahr Diyala tributary of the Tigris river.