Troops battle in sandstorm

A massive artillery barrage was today launched against Iraqi defences to the south of Baghdad. The latest phase in the attack on the Iraqi capital began as sandstorms slowed down American plans and forced the grounding of attack helicopters which had been pounding Republican Guard positions.

Strike aircraft are now flying from carriers in the Mediterranean to drop so- called "dumb" bombs - conventional unguided bombs - on dug-in tanks, bunkers and troop positions to clear the way for a ground assault.

American artillery rockets also opened up on the defences to the south of Baghdad, launching a ferocious assault on the Medina Division of the Republican Guard, regarded as the key to the city. The 10,000-strong elite division holds the south-western approach and is said to be one of the most hardened groups of Iraq's troops, having led the invasion of Kuwait in 1990.

The battle took a key step forward today as both parts of the double- headed American advance crossed the Euphrates river. The 7th Cavalry, spearheading the advance by the 3rd Infantry division in the west, crossed north of the town of Karbalah. The US First Marine Division crossed at Nasiriyah, 225 miles south of Baghdad.

The two elements can now join up, fan out and create a front more than 50 miles across, which can take on the three Republican Guard divisions once they have been "softened up" by air power.

But the advance across the Euphrates by the cavalry, who move in M-1 Abrams tanks and Bradley fighting vehicles, was made difficult by Iraqis taking advantage of virtually zero visiblity to attack. Small arms fire from snipers created serious problems, and A-10 tankbusters and F-15 fighter-bombers were called in to strafe Iraqi positions.

And the Marines only charged through Nasiriyah after a massive barrage of artillery and air power was laid down in advance, killing off irregular Iraqi resistance.

A Reuters correspondent with the column reported action which seems certain to have caused heavy civilian casualties. He said: "American tanks shattered low-rise brick homes with high-explosive shells from close range - sometimes as little as 100 metres. Bullets ripped through the flimsy walls. The heavy rattle of machinegun fire was almost constant as thousands of US troops forced their way through the city."

The action came as Iraq's information minister Mohammed Saeed al-Sahhaf claimed that coalition air strikes had killed 16 civilians in the past 24 hours, and injured 95 people. There were also claims that 30 Iraqi civilians had been killed in Nasiriyah.

In Washington, the Pentagon made clear today that it was prepared to alter its strategy, dig in and wait for reinforcements, if Iraqi Republican Guard troops inflict significant casualties.

The admission raised the possibility that the war could be extended to at least a month.

The coming battle between US forces and the Medina Division will be decisive. "This engagement will determine if this is a long or short war," an officer at the Pentagon told reporters. "If Iraq chooses to use chemical weapons it will be in this coming battle."

Meanwhile, it was the weather which inflicted a blow on the initial American plan to use Apache helicopter gunships to destroy the hundreds of Soviet T-72 tanks in the hands of the Republican Guards. Swirling sandstorms caused by winds gusting up to 50mph meant that the Apaches were rendered virtually useless and will be largely grounded until the weather improves.

The effectiveness of the Apaches was already in question after the gunships only managed to destroy 15 tanks in almost 100 sorties. The ageing T72s are little match for American Abrams tanks, but they have vast numerical superiority and US commander General Tommy Franks's strategy has relied on air power destroying the Iraqi armour before the US forces advance.

In the mean time F14 Tomcats and F18 Hornets are being launched from American carriers in the Mediterranean, including the USS Theodore Roosevelt, to keep up the pressure of airstrikes.

They have been given instructions to support American positions and hit targets they are given by US commanders on the ground.

And the planes are being equipped with cluster bombs - whose use is controversial because of the potential for unexploded bomblets causing civilian casualties.

Unguided - or dumb - bombs can be dropped during bad weather when mobile targets such as tanks and armoured personnel carriers, as well as troops on the move, cannot be targeted by precisionguided weapons which rely on visual identification of their targets.