Insurgents in Iraq have killed 14 US soldiers in just two days, the US military has announced.

Twelve troops died in four separate attacks in Baghdad, officials said, with another two killed by a bomb in the western province of Anbar.

US forces have begun a major offensive against militants linked to Al Qaeda north of Baghdad.

Elsewhere at least 15 people died and 40 others were hurt in a suicide truck bomb attack in northern Iraq.

The attack in Suleiman Beg, 90km south of Kirkuk, destroyed part of a local council office and several nearby homes.

The casualties included several women and children, hospital officials said.

Earlier, the commander of US forces in Iraq said he expected al-Qaeda in Iraq to respond to the military build-up around Baghdad with one of its own.

In an interview with a British newspaper, Gen David Petraeus said the truck bomb attack on a mosque in Baghdad that killed at least 78 people on Tuesday was an example of this.