Five US soldiers have been killed and three others wounded in a bomb blast in central Baghdad.

An Iraqi interpreter was also wounded in the explosion, which was the worst single attack on US forces in Baghdad in months.

The soldiers were on foot patrol in Mansour district when a suicide bomber wearing an explosives vest walked up to them and blew himself up.

Earlier, two suicide bombers have killed a total of six people in Diyala province northeast of Baghdad.

A woman blew herself up outside the home of tribal leader Sheikh Ghadban al-Karkhi in Kanan, north of the provincial capital Baquba, killing him and three others.

The sheikh, his daughter and two of his bodyguards were killed in the attack.

The second bomber blew himself up at the gate of a police station in the town of Shaharban, north of Baquba, and killed two people.

20 people, two of them police officers, were also wounded in the attack.