The US military said today it launched its biggest air offensive in Iraq since the 2003 invasion to root out insurgents near a town where recent violence raised fears of civil war.
Announced with media fanfare just hours after Iraq's parliament held a brief first meeting that did nothing to end a political stalemate over forming a government, the US military said 50 aircraft were taking part in the raids north of Baghdad.
The US military released to the media photographs of troop-carrying Black Hawk helicopters lined up in a row for the offensive. There were no pictures of warplanes.
A defence official at the Pentagon, who asked not to be named said it was a relatively large, but sought to downplay the scale of the operation. "It's not precision bombs and things like that," the official said.
Another official said it was "predominantly" a helicopter operation that involved UH-60 Black Hawk helicopters and other aircraft and the insertion of ground forces.
A military statement said "Operation Swarmer" involved more than 1,500 Iraqi and US troops and 200 armoured vehicles targeting insurgents active near Samarra, 100 km (60 miles) north of Baghdad.
A defense official in Washington said 600-700 of the troops involved were Iraqi government forces. The rest were Americans.
Iraqi Foreign Minister Hoshiyar Zebari said the offensive showed Iraqi forces, some facing accusations of cooperating with the rebels, are increasingly capable of securing the country.