US and British planes targeted Republican Guard forces just south of Baghdad this evening in perhaps the largest assault to date on the troops, US officials said.
Meanwhile, the Army's 3rd Infantry Division moved north this evening toward the Shi'ite holy city of Karbala, only 50 miles south of Baghdad, but was stalled by a sandstorm that blew out of the desert.
While Iraqi paramilitary units harassed coalition troops from the rear, US-led forces tried to maintain their advance on Baghdad.
The troops made a rapid advance under heavy allied air protection that wiped out a column of charging Iraqi armour and sent some of Saddam's outer defenses withdrawing toward the capital.
But the weather halted the long columns of thousands of vehicles that were stretched across the desert and farms.
In northern Iraq, coalition warplanes bombed a military barracks Monday, shattering windows for miles around and igniting huge plumes of smoke. Frightened residents fled the area around Chamchamal in a stream of cars, taxis and buses.
A top Kurdish military official, Rostam Kirkuki, said the Americans bombed the entire corridor between Chamchamal and Kirkuk, a key oil center.
An American officer confirmed Monday that US forces have been in northern Iraq for about 24 hours. He would reveal no details or numbers of the troops.
Fierce fighting was still erupting in southern Iraq. British troops were engaged in artillery exchanges with Iraqi forces on the outskirts of Basra, some of it heavy, British military officials said. British troops have remained outside the city, the second-largest in Iraq, unable to move through it because of pockets of resistance.
To the southeast near An Nasiriyah, a convoy of hundreds of vehicles including tanks, TOW missiles and armored personnel carriers was backed up along the road leading to a pontoon bridge across the Euphrates River.