US troops backed by planes and helicopters attacked Fedayeen militia loyal to President Saddam Hussein in the central city of Najaf, a Reuters witness said on Wednesday.
A-10 Warthog ground attack planes flew low over the city, opening fire on suspected Fedayeen fighters who have offered unexpectedly stiff resistance to the US-led invasion, said Reuters correspondent Kieran Murray, who saw the attack.
Lieutenant Colonel Chris Holden of 101st Airborne said the city was a centre of Fedayeen resistance.
"The target is to destroy Fedayeen units and anyone else trying to disrupt our lines of communication," he said. "We are going to destroy them."
Officials said the assault would also involve Apache attack helicopters, and that suspected Fedayeen positions were being hit with 30mm depleted uranium rounds - "tank killer" weapons that are capable of blasting through walls.
The attack on Najaf came as US forces pushed forward on a number of fronts - encircling the Shiite Muslim holy city of Kerbala and seizing a key bridge over the Tigris river near Kut, putting them in control of a major highway leading to Baghdad.
While the advance signalled US troops were surging into new territory, the action around Najaf showed that commanders were still working to secure areas behind the frontlines where sporadic resistance has continued.
{{/usCountry}}While the advance signalled US troops were surging into new territory, the action around Najaf showed that commanders were still working to secure areas behind the frontlines where sporadic resistance has continued.
{{/usCountry}}In Nassiriya, where civilians have been caught up in bitter fighting between militia fighters and US Marines, US forces on Tuesday began delivering water and ready-made meals in hopes of winning the trust of Iraqi civilians.