WASHINGTON - Howling winds swept thunderstorms and blinding clouds of reddish sand across the battlefields of Iraq yesterday, keeping U.S. troops from launching a crucial ground assault against Saddam Hussein's elite divisions outside Baghdad.
The forces of nature did not stop the Americans from raining bombs and artillery fire on Iraqi units dug in less than 50 miles south of the capital. But they did ground aircraft, preventing U.S. combat helicopters from attacking at least two heavily fortified Republican Guard divisions blocking the approach to Baghdad.
Under cover of the blowing sand, U.S. commanders positioned their forces and gave exhausted soldiers a respite and their first hot meals in days. Both sides are girding for what could be a decisive battle, possibly involving tens of thousands of soldiers, at what Gen. Richard B. Myers, the chairman of the Joint Chiefs of Staff, called "the doorstep of Baghdad."
In southern Iraq, there were reports of chaos in and around Basra, a city of 1.3 million, as Iraqi irregulars battled British forces arrayed outside the city. According to British and American officials, fighters loyal to Hussein were firing on members of Basra's Shia population, who might have begun an uprising against the regime.
Eyewitnesses said Iraqi soldiers lobbed mortar rounds at crowds of civilians in Basra. Meantime, British troops, using tactics honed during years of fighting urban violence in Northern Ireland, staged a raid on Hussein loyalists in the city and captured a local leader of the ruling Baath Party.
Maj. Gen. Peter Wall, commander of British forces in the gulf, said the unrest in Basra, Iraq's second-largest city, "could be the beginning of something important," which allied forces would hope to capitalize on.
From the rear of their push toward Baghdad, where American forces have suffered casualties during fierce fighting against pockets of regular troops and militias during the past few days, came reports of combat successes.
What was described as the largest ground skirmish of the war might have resulted in the deaths of as many as 500 Iraqi soldiers near the town of Najaf, about 100 miles south of Baghdad. No American casualties were reported.
Officials said that elements of the U.S. 7th Cavalry Regiment were attacked with rocket-propelled grenades from an Iraqi unit apparently headed for the town of An Nasiriyah, where Marines struggled for control of two key bridges on the long invasion route stretching north from Kuwait.
Some of the 7th Cavalry's equipment was damaged in the fight with the Iraqi troops, who were on foot and might have been regular soldiers, paramilitary forces or members of the Republican Guard. A senior defense official told the Associated Press that initial reports were sketchy and that the number of Iraqis killed might have been closer to 150.
In another battle, U.S. Marines captured about 170 Iraqi irregulars, possibly members of the fedayeen militia, who had been firing on American forces from inside a hospital in the An Nasiriyah area.
The Americans found a cache of weapons, including an Iraqi tank, inside the hospital compound, as well as a grimmer discovery: more than 3,000 chemical weapons suits with masks. But U.S. officials said again that they have yet to find evidence of Iraqi chemical or biological weapons.
A total of more than 3,500 Iraqi soldiers have been taken prisoner, officials said.
President Bush, during a visit to the Pentagon, said the U.S.-led invasion force was "making good progress." But he warned that "we cannot know the duration of this war."
There was also a sobering message from Bush's main ally, British Prime Minister Tony Blair, who is flying to Camp David in Maryland today for two days of meetings with the president. During an hour-long news conference in London, Blair predicted that "there will be resistance all the way to the end of this campaign."
In Washington, Defense Secretary Donald H. Rumsfeld said U.S. forces were still "much closer to the beginning" of the war "than the end." He cautioned that the fighting "could well become more dangerous" soon. Rumsfeld also said he did not know whether the war would last for "days, weeks or months."
Iraqi television broadcast a new message in Hussein's name, urging Iraq's tribes and clans to "consider this to be the command of faith and jihad" to fight the U.S.-led forces. Early this morning, coalition aircraft bombed the Iraqi TV building, knocking the signal for the 24-hour Iraqi satellite TV station off the air.
American bombing of Baghdad went on throughout the day, striking Hussein's intelligence headquarters and other military targets but again sparing residential neighborhoods of the city's 5 million inhabitants.
The ground conflict of the second gulf war has lasted longer than that of the first gulf war, in 1991. As the first week of the war neared an end, more than 22 Americans have died and 14 others are either missing or captured, a relatively light casualty count for a war involving perhaps 500,000 or more combatants.
A total of 20 British troops have also been killed, including two in a "friendly fire" incident yesterday.
Though the U.S.-led forces have discovered no evidence of chemical or biological weapons in Iraq, there is increasing concern that such weapons might be used against American forces in coming days. As American troops draw close to the capital, perhaps within 30 miles, there are fears that Iraqi commanders will be free to unleash nerve gas or other agents.
Rumsfeld confirmed that there have been "scraps" of intelligence information to that effect. "But whether it'll happen or not," he said, "remains to be seen."
Throughout the day, the Bush administration signaled its apparent concern that public support for the war could be shaken by the cumulative impact of round-the-clock war coverage and live TV reports from the battle zone. Military officials and members of Bush's Cabinet repeated similar messages, designed to dampen any lingering expectation that the conflict would be a cakewalk.
At the same time, Rumsfeld testily denied that senior administration officials and military leaders had led the public to believe that the Iraqi leadership would likely be stunned into submission by an all-out opening air campaign of "shock and awe."
Myers told a Pentagon briefing that he did not mean to imply that the United States expected to gain a quick surrender by Hussein when he said, three weeks ago, that the best way to shorten the war "would be to have such a shock on the system that the Iraqi regime would have to assume early on the end was inevitable."
Myers and Rumsfeld also rebutted criticism from some active and retired military leaders that Pentagon planners had failed to deploy a large enough ground force in the gulf region. Critics have charged that the lack of an additional armored division had left the supply line stretched thin and vulnerable to deadly ambushes, including one that killed seven soldiers and left five American prisoners in Iraqi hands last weekend.
Myers noted that American forces, moving with unusual speed, had managed to make it to the outskirts of Baghdad in a matter of days. He added that many of the casualties suffered are "due to Iraqis committing serious violations of the law of armed conflict in the Geneva Convention by dressing as civilians, by luring us into surrender situations and opening fire on our troops."
The rain and sandstorms that swept across Iraq overnight slowed the ground advance but gave forward units of the U.S. 3rd Infantry Division a badly needed breather after their rapid advance out of Kuwait. Journalists traveling with elements of the division reported that food, water and gasoline were in short supply, though not severely so.
Bloody fighting to the rear has complicated efforts to resupply the long columns of U.S. forces stretched out for hundreds of miles across the Iraqi desert. From the western front came a report that hundreds of Iraqi nationals had been crossing the border from Jordan, apparently in hopes of joining the fight against the American-led invasion.
U.S. military officials, who are beaming round-the-clock radio broadcasts to the 23 million citizens of Iraq using five airborne transmitters, issued a new warning: Stay off the highways.
Maj. Gen. Victor Renuart, director of operations at Central Command in Doha, Qatar, said America was not imposing a "no-drive zone" in Iraq. But he did advise Iraqis to "stay off the roads" because "the battlefield is a very hazardous location."
The warning came one day after five Syrians were killed and 10 were injured when a U.S. jet attacking a bridge in western Iraq bombed a bus in what military officials called a tragic accident.
Renuart also said that six satellite jamming devices Iraq was using in an effort to block precision-guided American missiles and bombs had been located and destroyed. The devices, he added, had had no effect on U.S. military operations.
On Monday, Bush called Russian President Vladimir V. Putin to protest the sale of sensitive technology to Iraq, including jamming devices. The Russians have denied providing such equipment.
U.S. bombing runs continued over northern Iraq, including against Republican Guard targets near the Kirkuk oilfields.
Sun staff writer Todd Richissin contributed to this article.