By Thomas W. Lippman, Peter Baker and Terry M. Neal
Washington Post Staff Writers
Wednesday, March 26, 2003; 6:46 PM

Battling sandstorms and then rain that turned the desert to tank-trapping mud, U.S. troops on the southern approaches to Baghdad faced an audacious challenge from Iraqi defenders tonight when a convoy of fighters were reported rolling south from the capital to confront the Americans.

Republican Guard units began moving out of defensive positions today in a convoy of 1,000 military vehicles that was reportedly heading in the direction of U.S. Army forces around the city of Karbala, about 50 miles south of Baghdad, U.S. military officials said. Another contingent of 2,000 troops from one Republican Guard division was on the move to reinforce another one facing U.S. troops outside the capital.

That Saddam Hussein would send his premier fighters this early was seen by some U.S. military officials as a bold, and highly risky move for the Iraqis, who will be exposing their best troops to devastating American air power.

Some Pentagon officials were practically gleeful at the development, with one official saying the column would be "like shooting fish in a barrel" or like "a turkey shoot."

Another official in Washington was far less sanguine.

"This is their turf," the official said. "They've probably done exercises there their whole life. The defense of Baghdad is all they've trained for."

U.S. jets began bombing the front of the convoy after receiving confirmation that the column carried fighters. Eventually, B-52s flew over, dropping 500-pound bombs every 500 meters along the length of the convoy. The casualty total was not immediately known, but the attack appeared to add significantly to the Iraqi militia losses in recent days.

U.S. officers said they also believed troops from the Special Republican Guard, the most select military element charged with protecting President Saddam Hussein, have begun moving out of Baghdad to southern Iraq to stiffen the resolve of regular army units and bolster hit-and-run guerrilla actions waged by paramilitary squads.

Both moves took U.S. military planners by surprise-the Republican Guard was expected to hold back to defend Baghdad; the Special Republican Guard rarely leaves Baghdad-and could suggest a more aggressive strategy by Hussein. The Iraqi president may be emboldened by the capture of several Army soldiers and the persistent harassment U.S. and British soldiers have endured in southern Iraq. Instead of simply hunkering down in Baghdad, as some analysts expected, Hussein now seemed to be signaling that he would try to take on his attackers more directly.

"That tells me that he may be looking at making a stronger defensive stand south of Baghdad proper rather than waiting until we get into the city itself," said Lt. Col. George Smith, a top war planner for the Marines here. "We are adapting some of our tactics based on what the enemy is doing."

The reports followed a difficult day of day of fierce fighting and dogged Iraqi resistance, which began with the devastation of a Baghdad neighborhood that was apparently caused by errant U.S. air strikes. Iraqi authorities said at 14 civilians were killed and another 30 injured.

About the same time, British military officials quoted by the Reuters news agency reported another group of Iraqi tanks and armored personnel carriers moving around Basra and being hit by airstrikes.

U.S. forces today resumed their aerial bombardment of Baghdad after sunset Iraq time, undeterred by the possibility that missiles or bombs may have gone astray this morning. Thunderous explosions resounded through the capital.

If the earlier explosions in the Baghdad neighborhood were the result of misdirected bombs or cruise missiles, this would be the first major incident in which civilians died as a result of a U.S. airstrike error. Up to now, U.S. officials at every level have been proudly emphasizing the care with which airstrike targets are selected and the precision with which they are struck. Just this morning, President Bush hailed the "lethal precision" of the air campaign.

At the daily military briefing for reporters at the U.S. command center in Doha, Qatar, Army Gen. Vincent Brooks said he could not confirm that U.S. strikes had hit the market. "We don't know that those are ours. We can't say that we had anything to do with that," he said.

Reporters who had seen television images of smoking wreckage and bleeding victims being taken away on stretchers asked what other cause there might have been, given that Baghdad is the target of a massive U.S. airstrike campaign that continued throughout today.

"I don't know," he said. He acknowledged that "mistakes can occur," but he said Iraqi propaganda and deceptive tactics on the battlefield, including the dressing of troops in civilian clothes, show that the evidence of the naked eye is not to be trusted. Hours later, Army Maj. Gen. Stanley McChrystal, briefing reporters at the Pentagon, said missiles did hit the Baghdad neighborhood but it was not certain that they were U.S. missiles.

Meanwhile, the war continued through another day of blinding sandstorms and battlefield confusion. Indications mounted that U.S. and British forces were encountering stiffer resistance than they expected and Iraqi tactics that forced allied commanders to rethink their next moves. Nevertheless, President Bush, addressing troops and military families at MacDill Air Force Base in Florida, headquarters of the U.S. Central Command, pledged, "We will be relentless in our pursuit of victory," undeterred by the difficulties of the moment.

"Nothing, nothing will divert us from our clear mission," he said. "We will press on through every hardship, we will overcome every danger and we will prevail."

U.S. airstrikes knocked Iraqi television off the air. It subsequently resumed transmitting, although not on all channels, as the pounding of military and Baath Party targets in Baghdad continued. Brooks said the television building was considered a military target because it was used by the government of President Saddam Hussein "to issue instructions to regime forces."

U.S. soldiers and Marines headed for Baghdad remained becalmed in the desert about 50 miles south of the capital, hunkering down against the relentless blowing sand and repairing equipment. The biggest ground battles of the war are expected when visibility improves and the wind diminishes and those units confront Iraqi Republican Guard units defending Baghdad.

A Pentagon official said the Third Infantry Division and 1st Marine Expeditionary Forces are regrouping now to hit the Medina division and the Baghdad division of the Republican Guards respectively. After those pivotal battles, the forces would then turn toward each other (the Army heads east, the Marines head west) to mass and concentrate forces.

"We're not going to rush headlong into the city, absolutely fruitless to do so and suicidal at best," the official said. "You want to establish parallel lines, prevent fratricide and strengthen your rear. The goal is to encircle the city [Baghdad] and take it on our terms."

Brooks said U.S. commanders had received reports that bridges leading into the capital have been wired for demolition by Iraqi forces. "It just reminds us that this regime will go to extraordinary lengths to protect itself."

The Pentagon acknowledged today that it had lost an M1A1 Abrams tank in a fierce battle outside the town of As Samawah yesterday, the first time an Abrams has ever been destroyed in battle. The Third Squadron, 7th Cavalry Regiment-the tip of the spear of the armored column heading toward Baghdad-also lost two M2 Bradley Fighting Vehicles.

Brooks said the discovery by U.S. troops of 3,000 chemical protective suits in a hospital used by Iraqi military units in Nasiriyah, in southern Iraq, reinforced U.S. suspicions that Iraq has chemical weapons and plans to use them. "We remain convinced that this regime has not only the means but also the will to use weapons of mass destruction. What we found last night inside of that hospital reinforces that."

Like all other U.S. and British briefers, civilian and military, over the past few days, Brooks said neither the weather nor any possible bridge demolitions nor poison gas nor continuing harassment of U.S. units by Iraqi irregulars will deter the U.S. led coalition from its objective: removal of Hussein's regime.

"We have forces that are arrayed throughout all of Iraq at this point, so if you are an Iraqi wondering where it's going to come from, it's going to come from everywhere," he said.

Outlining the progress of the military campaign over the last day, Brooks said troops from the U.S. Army's V Corps had engaged in a series of battles with Iraqi troops southeast of Najaf. The battle lasted about three to four hours and inflicted "significant damage" on Iraqi forces, he said. Several U.S. vehicles were damaged.

He said the 1st Marine Expeditionary Force was involved in combat near Nasiriyah and British troops battled Iraqis on the Faw Peninsula and in Basra, the country's second-largest city, in southeastern Iraq. He compared Iraqi paramilitary forces who he said have been firing on their own people in Basra to "global terrorists."

In southern Iraq, Brooks said the port of Umm Qasr has now fully secure and relief supplies have begun to flow to the people of Iraq's populous southeast, who have been running short of food and water. Television cameras in Safwan, near Umm Qasr, showed Iraqis storming trucks bearing food packages, some of them throwing fists and elbows as they fought for the supplies.

Another humanitarian crisis may be developing in Nasiriyah, site of fierce fighting between Iraqi troops and U.S. Marines trying to secure two key bridges that are essential to the movement of U.S. convoys. Television reporters who reached the city of 300,000 people said the residents are running out of food and water.

Bill Garvelink, deputy assistant director of the U.S. Agency for International Development, said the relief team that will be deployed in Iraq is "the largest disaster assistance team we've ever put together," with more than 60 people. "It's much larger than Afghanistan."

The situation in Basra was confused and confusing. Reports on Tuesday night of a mass uprising against Hussein's regime appear to have been exaggerated, but there were indications today that at least some Basra civilians-perhaps desperate for water-had tried to attack Iraqi troops. By some accounts, the Iraqi military units holding out in the city are Fedayeen militia irregulars who are Sunni Muslim and loyal to Hussein, sent from other parts of Iraq to try to maintain control of Basra, where the population is largely Shiite Muslim.

"Truthfully, the reports are confused, but we believe there was some limited form of uprising," British Prime Minister Tony Blair told the House of Commons in London. "It is important that we give support to those people in Iraq who are rising up to overthrow Saddam and his deeply repressive regime."

British artillery units have been shelling Iraqi positions inside the city, the Iraqis are using civilians as human shields, according to Chris Hughes, a Royal Horse Artillery gunner. "There's some tanks refueling, five or six of them, but we couldn't engage them because they were right next to a built up area, a hospital," he told the Reuters news agency.

Shelling resumed after dark Iraq time Wednesday. "That is British artillery and that would be aimed at targets in and around the Basra region," said Lt. Chris Head, 24, the platoon commander of the Fusiliers, on the highway about eight miles from the city center. With the pro-Hussein security forces and militia interspersed among the civilian population, Head said "it makes the question of target identification all the harder."

The Shiites of Southern Iraq did rise against Hussein, in response to U.S. appeals, during the 1991 Desert Storm campaign, but were crushed when the expected U.S. aid did not materialize. Many analysts have speculated that the people of Basra, burned by that experience, are waiting this time to find out if the allies are serious about ending Saddam Hussein's rule.

British troops have been firing artillery and mortar rounds into In Washington, the Defense Department identified two Marines and one Army soldier who died in combat in Iraq, bringing the number of U.S. deaths to 22. The victims were Army Spec. Gregory Sanders, 19, of Indiana; Marine Corps Lance Cpl. Randal Rosacker, 21, of San Diego, and Lanc Cpl. Brian Buesing, 20, of Cedar Key, Fla. In addition, the Pentagon reported that a second soldier died of wounds suffered in a grenade attack on a 101st Airborne Division tent in Kuwait. He was Air Force Maj. Gregory Stone, 40, of Boise, Idaho.

Washington Post correspondents Alan Sipress, Susan Glasser, Keith B. Richburg, Willim Branigin and Jonathan Weisman contributed to this report.