The "Screaming Eagles" began the third day of their campaign to secure the areas south and north of the holy Shiite city by sending in another batallion of Apache attack helicopters to support infantry troops, division Aviation Brigade commander Colonel Greg Gass told AFP.

Gass said the Apaches flew out early Tuesday to join a batallion of the smaller, less powerful Kiowa Warrior helicopters south of Najaf.

The brigade's 3rd Batallion of Apaches resumed flights north of Najaf to also support 101st infantry troops who were fighting an unidentified Iraqi mechanized division, according to Gass.

The 101st began its campaign around Najaf on March 30, with the primary aim to secure the area for communication and supply lines in the US military's push towards Baghdad.

Najaf and Karbala, another city important to Iraq's majority Shiite population a further 80 kilometres closer to Baghdad, are vital to the US forces because important highways lead from there to the capital.

Gass said he had no reports of the outcome of Tuesday combat by 10:00 am (0700 GMT).

In Monday's battles, Gass said the 3rd Batallion Apaches destroyed a "batallion's worth" of Iraqi soldiers and S-60 anti-aircraft 57mm weapons, without going into specific numbers.

Gass described the combat as the heaviest his forces had been involved in since the start of the war on March 20.

"They (the Iraqis) fought pretty hard from first light (into the afternoon)," Gass said, adding eight Apaches sustained various levels of damage.

"Eight aircraft were hit anywhere from just a hole in the rotor to significant tail damage," Gass said.

Gass and other 101st officers said that much of the small arms fire that had struck the helicopters orginated from behind houses and other buildings.

SPACE.WIRE