U.S. forces launch massive air attack in Iraq

American and Iraqi troops have launched what the U.S. military says is its largest air offensive in Iraq since the 2003 invasion.

The assault, dubbed Operation Swarmer, is focused on a 'suspected insurgent operating area' northeast of the city of Samarra and could last for several days, said officials.

The operation came as a new poll showed increasing pessimism about the war in the United States, with the number of people who believe a U.S. victory in Iraq is "likely" falling 40 percentage points over three years.