U.S. ground forces paused in their advance towards Baghdad, in part to rest and regroup and in part because a massive sandstorm made waging war difficult. But, according to Pentagon reports, the respite ended late in the day for the U.S. 7th Cavalry near An Najaf, about 100 miles south of Baghdad, when they were attacked by Iraqi forces.

In the south, British military forces prepared to move into Basra after a days-long battle with defenders loyal to Iraqi president Saddam Hussein. British officials said that a civilian uprising against Hussein's government may have already begun inside the city.

BAGHDAD ADVANCE STALLED

Both the deliberate pause by the U.S. Third Infantry and the driving sandstorms put off for a least a day what many observers think will be an important engagement with a division of Iraq's elite Republican Guard that is defending the southern approach to Baghdad. Although many helicopters found it difficult to launch attacks against the Republican Guard's armored Medina Division arrayed to defend the Iraqi capital, U.S. artillery subjected the Iraqi defenders to a daylong barrage. Pilots bombing Iraqi positions south of Baghdad switched to satellite-guided weapons because of the severe weather.

For U.S. soldiers, this was a day to "refit, refuel and rearm," said Capt. Anthony Butler, 32, of Helena, Mont., commander of the 2nd Brigade's headquarters company. But the soldiers of the 7th Cavalry bracing against the driving sandstorms were attacked by Iraqis who used rocket-propelled grenades, according to incomplete Pentagon reports that were not corroborated by eyewitness. The Pentagon officials said 150 attackers may have been killed and reported no U.S. casualties.

FIGHTING AROUND BASRA

British forces had held off attacking Basra directly to avoid civilian casualties. But late in the day, they directed artillery fire into the city itself, barraging Iraqi mortar positions soon after receiving reports that Iraqi troops had begun firing on a crowd of civilians.

British officials said they had few details a bout the extent of they called an "encouraging" insurrection in the city of 1.3 million. Iraqi officials denied there was an uprising.

Earlier in the day, Iraqi tanks had mounted a counter-attack, charging toward British positions west and south of the city to test their defenses. The British reported destroying 20 T-55 tanks and other armored vehicles. Two British soldiers were killed in a friendly-fire incident, when their tank was fired on by another tank, officials confirmed.

ELSEWHERE IN THE SOUTH

There were skirmishes in much of the rest of the south as well. A running series of firefights in the port of Umm Qasr has delayed the arrival of humanitarian aid, which the military hopes to begin shipping into Basra, which has a food and drinking water crisis. But by the afternoon, British officials said the port had been secured In Nasiriyah, Marine units turned up evidence of a base of a paramilitary group called Saddam Fidayeen located in a hospital, where they took 170 prisoners and found 200 weapons, ammunition and 3,000 chemical protective suits with masks and atropine injectors as well as U.S. Army uniforms believed to be from the soldiers captured last week, officers said. BUSH PROMISES VICTORY

President Bush in a visit to the Pentagon, said U.S. and other forces in the Persian Gulf are "on a steady advance" and "making good progress." The president said that while no one can predict how long the war will last, "We know its outcome. We will prevail, the Iraqi regime will be disarmed, the Iraqi regime will be ended, the Iraqi people will be free and our world will be more secure and peaceful."

Still Bush administration officials had to defend themselves against criticism that their war plan underestimated the size of the force needed to subdue the Iraqi military, that they unduly built expectations at home that the war would end quickly and that they have failed to deliver on promises of immediate humanitarian assistance for the Iraqi population. The president urged Congress to act quickly on his supplemental request for $74.7 billion to help underwrite part of the cost of the war and the initial reconstruction of Iraq, as well as provide funds for homeland defense and some key allies in the Middle East.

-- James L. Rowe Jr.