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.