The US army's elite 101st Airborne Division stepped up its campaign around the city of Najaf, 150 kilometers (95 miles) south of Baghdad, flying in Apache and Kiowa attack helicopters to support infantry troops, officers said.

The 101st Airborne and the US Army's 3rd Infantry Division were poised for a concerted drive against Baghdad with two formations of US marines to their east also moving toward the capital.

The action Tuesday followed a day of fighting Monday which Colonel Greg Gass, the 101st's aviation brigade commander, described as the heaviest his forces had been involved in since the start of the war on March 20.

"They fought pretty hard from first light (into the afternoon)," Gass said, adding eight Apaches sustained hits "from just a hole in the rotor to significant tail damage."

US officials also said the Army 3rd Infantry Division attacked Iraqi positions Monday in quarries below Karbala, another Shiite Muslim holy city 70 kilometers (45 miles) to the north of Najaf.

They said elements of the 3rd Infantry Division also hit out northward at what they called pockets of Iraqi resistance in the area.

Two air defense artillery systems, two armored personnel carriers, one artillery piece and nine technical vehicles were destroyed, they said. Several Iraqis were killed and about 30 taken prisoner.

The tank-busting Apaches, as well as British and US warplanes, have been softening up the area around Karbala where the Republican Guard's armored Medina division was reported to be lying in wait to defend Baghdad.

US-British forces kept up their bombardment of the capital Tuesday, hitting the main presidential palace complex for the second consecutive day.

Three days after a suicide bombing killed four US soldiers, American troops fearful of a fresh attack opened fire on a civilian vehicle at a military checkpoint at Najaf, killing seven women and children, officials said.

Navy Lieutenant Commander Charles Owens said at US headqarters in Qatar that the victims were in a vehicle that failed to stop despite warning shots fired by US troops. Four people in the vehicle escaped unharmed.

US marines were busy securing supply routes and mopping up areas of southern Iraq. Officials said they seized Sunday a huge ammunition supply depot with rifles, rocket-propelled grenades, mortars and other weapons.

"We continue to press the attack against the enemy, conducting spoiling raids," said Colonel Bennett Saylor, 1st Marine Division chief of staff. No further details were available.

British forces besieging the port of Basra said they were waiting for more manpower before trying to take the southern metropolis.

They kept up their siege after taking the neighboring town of Abu al-Khasib, 20 kilometers (12 miles) to the southeast, and rattling the western suburbs of Basra with artillery Monday.

In London the defense ministry said a British soldier had been killed "during an explosive ordnance disposal operation" in southern Iraq. It gave no further details.

The death brought to 26 the number of British soldiers killed since the beginning of the war nearly two weeks ago, 15 of them in accidents. Five have been killed by friendly fire and five have died in combat.

SPACE.WIRE