Both aircraft came down over Karbala, where there has been fierce fighting between the Army's 3rd Infantry Division and Iraqi troops, including Saddam Hussein's elite Republican Guard forces.

The Hornet is designed for carrying out both bombing raids and fighting other aircraft.

The Black Hawk was the second US helicopter to go down in combat.

An Army Apache assault helicopter crashed on March 24 during an assault on Republican Guards.

Its two pilots were captured by Iraqis.

The UH-60 Black Hawk is one of the Army's main utility and troop transport helicopters.

Each one is flown by a crew of four and can carry up to 11 soldiers.

Meanhwhile, a US Marine was killed when he was struck by low-hanging power cable as he travelled in a truck outside Nassiriya.