BBC News with Jonathan Izard

A group of suicide attackers has stormed an Iraqi army base in Baghdad, drawing American troops into the fighting just days after the United States formally ended its combat operations in the country. At least 12 people were killed and more than 20 wounded in the assault by militant gunmen and bombers. Two of the attackers managed to get into the base, and an Iraqi officer said American forces were called in to help in a gun battle with them. From Baghdad, Gabriel Gatehouse.

The Americans always said that the fifty-odd thousand troops they've still got here are of course authorized to fire in self-defence, but it is actually quite unusual for the Americans to engage this actively in an operation usually they provide air cover and other sort of expertise. Here it seems they went a little bit further, and it seems that while the Americans are still here, this is resource that the Iraqis can call upon. And these attacks do take place on quite a regular basis, so we can assume that they will probably call upon them again in the future between now and the pullout date, which is at the end of next year.