A spokesman for coalition military forces, Lieutenant Colonel George Krivo, told reporters the new policy, known as "Operation Iron Hammer," may not be a short-term mission.

"We expect these types of targeted, anti-terrorist operations will continue and intensify as long as necessary," he said.

Operation Iron Hammer intensified Wednesday, signaling a more aggressive U.S. strategy to go after insurgents waging a deadly guerrilla war across Iraq.

Using Bradley fighting vehicles and attack aircraft, U.S. forces in Baghdad Wednesday destroyed a warehouse believed to have been an insurgent meeting place, and chased nearly a dozen men attempting to set up a mortar position. Two of the men were killed and several others were captured.

Air power has been used several times this month on insurgent targets. F-16 jets have dropped bombs on suspected sites in Fallujah and Tikrit, where two American military helicopters were shot down. Lieutenant Colonel Krivo says the military is identifying targets, mostly with the help of local Iraqis who are providing U.S. troops with valuable intelligence.

U.S. forces are also clamping down on security around the so-called green zone in Baghdad where the Coalition Provisional Authority is headquartered.

A major bridge that connects the green zone to southern Baghdad, has been closed indefinitely, following reports that insurgents used the bridge to launch mortar attacks against the Coalition Authority headquarters earlier this week.

The bridge, which had been sealed off to the public since April, reopened with much fanfare only two weeks ago.