One American soldier and two Iraqi women have been killed in separate attacks in Iraq.

The U.S. military says three soldiers were wounded in a roadside bomb blast in the town of Baquba, northeast of Baghdad late Wednesday. One soldier later died of his injuries.

Also on Wednesday, a spokesman for the British forces in the southern Iraqi city of Basra said two Iraqi women working for a contracting firm were killed while returning home, when assailants fired on their taxi.

The motive for that attack was not clear. A number of attacks in Basra has been blamed Shi'ite militias enforcing strict Islamic standards.

Meanwhile, U.S.-led coalition authorities say the Federal Bureau of Investigation will investigate Tuesday's killing of two American civilians and their Iraqi translator on a road south of Baghdad.

Coalition officials say investigators will first try to determine if the gunmen were impostors or Iraqi police working with insurgents.

The three, who worked for the Coalition Provisional Authority, were killed by gunmen pretending to be Iraqi police near the town of Hillah. A coalition spokesman, Dan Senor, described the incident as a targeted act of terrorism.

The Americans were the first working for the U.S.-led coalition to be reported killed in Iraq since the start of the war almost a year ago.

Some information for this report provided by AP, AFP and Reuters.