A sixth Blackwater guard has brokered a deal with prosecutors, pleading guilty to killing one Iraqi and wounding another, and is to testify against his former colleagues.

Uncertain status

Blackwater is the largest of several private security contractors operating in Iraq [AFP]
The presence of private security firms such as Blackwater in Iraq has proved highly controversial, with the Iraqi government saying the firms act with impunity and that their legal status is unclear.

Blackwater, based in the state of North Carolina, is the largest contractor providing security in Iraq.

Much of its work for the US state department is in protecting US diplomats in the country.

The company has not been charged in connection with the shooting.

Critics say a new US-Iraqi security agreement which went into effect on January 1, replacing a United Nations mandate, still does not clarify the rules under which security firms in Iraq operate.