The Marines had keys to the rooms in the Palestine Hotel, but in cases where the doors were bolted, they kicked them down, rousting journalists from their beds and pointing M-16s in their faces, footage from Associated Press Television News showed.
Outside the hotel, hundreds of Iraqis swarmed, appealing for law and order in the city. Marines trying to placate the crowd moved out in front of the barbed wire, but the crowd surged toward them and they struggled to keep from being thrust into the wire themselves.
Among the crowd was a sign reading, in English, "Bloody liberation movie is started. Bad director."
Barbed wire has been strung around the entire hotel complex, and dozens of Marines were on sentry duty.
Elsewhere in the capital, Iraqi police stepped up patrols and volunteers directed traffic Tuesday in a slow return to law and order.
Looters broke into government food warehouses in Baghdad and used wheelbarrows and pickup trucks to carry off sacks of sugar, flour and other supplies.
The looting and arson reached Iraq's National Library, which on Tuesday was a smoldering three-story shell, its floor covered with the ashes of books, possibly including some irreplaceable, centuries-old Arabic manuscripts. Nearby, the library of the Religious Affairs Ministry, home to invaluable religious texts, also was looted and gutted by fire.
Nevertheless, the lawlessness in Baghdad has eased considerably from last week, and looting has all but ended.
Groups of Marines were on foot patrol in some neighborhoods, looking for weapons caches and gunmen and seeking to deter looters.
Marine spokesman Cpl. John Hoellwarth said five joint patrols by Marines and Iraqi policemen went to work on Monday to try to restore law and order, and "today there are many more."
"We appealed for 150 policemen to join us and we got 750 to 1,000," he added.
Teenagers and older men directed traffic. Many drivers seemed happy to see the self-appointed traffic cops and flashed them thumbs-up signs, but only a few actually followed their directions.
Marines handed out fliers urging people to stay in their homes after dark for their own safety.
"To avoid placing coalition forces in a position where we must make a distinction between you and terrorist or criminal elements during a time of limited visibility, please do not leave your homes during this time," the message said.
The appeal, printed in English on one side, in Arabic on the other, stopped short of imposing a curfew, but urged people not to leave their homes between evening prayers and morning prayers.
The message also asked people not to carry anything that looks like a weapon, to pull off to the side of the road to let convoys pass, and to tip off coalition forces to any dangers they might face.
Power, cut off for nearly two weeks in most of Baghdad, will be restored in 48 to 72 hours to some parts of the city, Hoellwarth said.
At Mansour Hospital in northwest Baghdad, American civil affairs officers met with the staff to determine the hospital's needs and combed the building because of rumors that members of the Fedayeen paramilitary force were hiding there.
Another platoon tried to clear a city park of hundreds of Iraqi mortar and artillery shells. Civilians begged the troops to take the munitions away because children were starting to play with them.
On Monday, two Army soldiers were killed and two wounded when a grenade exploded accidentally at a checkpoint south of Baghdad. A third soldier was killed and another wounded in an accidental shooting near the Baghdad airport.
After their raid at the Palestine, Marines were seen guarding suspects in a hall; interrogating a man who claimed to be a cameraman; and breaking down a door to get to the roof.
Four Iraqi men who did not have proper identification were detained in the raid that began at about 7 a.m.
The Marines had information that Fedayeen paramilitary fighters might be hiding there, military officials said. Arms were also believed to be hidden there.
The raids hit the 16th and 17th floors, where journalists with CNN, Turkish TV, Japanese TV and other networks were staying. It was unclear how many rooms were searched in the 18-story hotel overlooking the Tigris River.
Last week, an American tank opened fire on the Palestine Hotel because of what the U.S. military said was enemy fire coming from the building. Two journalists were killed and three others wounded.
It was one of several incidents that led international press organizations to accuse the United States of targeting journalists. The same day the tank attacked the Palestine, Arab television stations Al-Jazeera and Abu Dhabi were hit, and an Al Jazeera journalist died.
Al Jazeera's compound in Basra was reported hit several times earlier in the war.
Iraqi state television was also bombed; Central Command said it was a legitimate command-and-control target because it broadcast instructions to troops, but some human rights groups contend that targeting a civilian television station violated the Geneva Conventions.