Lieutenant Colonel Pete Owen said reinforcements had been sent overnight to the front line, where a marine battalion was taking on Iraqi fighters using rifles, automatic weapons and rocket-propelled grenades.

"They are very close to Saddam City and they have just begun engaging the enemy," he told an AFP reporter travelling with the marines.

Three marines had already been wounded in the fighting on Tuesday evening. The battle erupted after the marines swarmed into Baghdad across the Diyala river.

SPACE.WIRE