By JERRY SCHWARTZ
AP National Writer

At Las Vegas resorts, they were taking no chances _ guests were asked for permission to inspect their trunks when they handed over cars for valet parking.

At Georgia's Lake Lanier, a security boat was on patrol to protect a major source of power and drinking water. In Arkansas, officials announced that the state fair would open Friday as scheduled _ but backpacks will be forbidden.

Security nationwide _ already tightened after the Sept. 11 attacks on the Pentagon and the World Trade Center _ has been tightened again, as authorities fear that allied strikes against Afghanistan might inspire more terrorism.

But the new measures have not necessarily calmed the nerves of an American public that has seen the damage terrorists can do. While some are going about their business, others say there can be no business as usual.

Terri Legg, 39, and Freddie Foster, 43, of Elmer, N.J., considered driving to Philadelphia on Monday to shop and sightsee. Instead, they went shopping at a mall closer to home.

"If there's going to be an attack, they'll go for a place with thousands of people, and Philadelphia is very congested," Foster said. "We're looking to go to places where it's a little more safe, a little less crowded. We've told our kids to lock the doors, too. Before, it was like `Who would want to break into our house?' Now, you don't know."

Jim Furlan and his wife, Cheryl, waited at Chicago's O'Hare Airport for the airliner that would take them home to Los Angeles. Jim was OK with flying, if "a bit queasy." There was no way Cheryl would get on a plane _ except that their two daughters, ages 3 and 5, awaited them.

"I feel sick," she said.

Estelle Faryon, 64, of Winnipeg, Canada, a visitor to San Diego, was on a cruise when she caught herself looking over the ship's rail and watching a fishing boat approach.

"I was watching to make sure it didn't come too close. I never did that before," she said.

The calls for gas masks and American flags picked up again at the Ax-Man surplus store in St. Paul, Minn. Although the store stresses the gas masks they sell are novelty items and not intended for legitimate use, manager Kim Mourning said the place has a waiting list.

"Everyone from mothers to older people have called," she said. "Some don't even want to be on a list _ they want it now."

Around them, they saw signs that government was taking the threat very seriously. In downtown Los Angeles, newly placed concrete barricades manned by police officers protected City Hall. In Atlanta, police assigned to monitor public schools were put on heightened alert.

Railroads restricted shipments of hazardous cargo, diverting them from heavily populated areas. Trucks and other vehicles were searched before entering downtown Minneapolis.

"I don't want to stop my life. In the beginning, yes, I did things differently. Now I'm getting back to normal," said Gina Morgan, a 29-year-old accountant from Inkster, Mich., who visited Fairlane Mall in Dearborn to get her nails done.

"I'm a little more aware of my surroundings. I look at people now, and I wonder, `Could they harm me or are they just shoppers or are they just casing the place?'"

Nancy Fritz, a nursing student from Irvine, Calif., studied for her midterms in the courtyard of a Phoenix mall while her husband attended a convention.

"For me, especially living near Hollywood, where most of America's culture is disseminated to the world, the possibility of retaliatory strikes now seems very real. I'll probably start to stockpile bottled water and nonperishable food supplies," she said.

Still, "I can't see myself taking a vacation in Afghanistan any time soon, but other than that, I won't change much in my life."

There is plenty of that kind of fatalism. "We're aware that anything can happen at any given time. But what can we do? I'm not scared. I continue to do what I have to do," said Crystal Drysdale of Temple City, Calif., as she rode the subway through Los Angeles with her friend, Sharon Cooper.

"My mom has cancer right now," said Cooper. "I'm scared of that."

But for others, carrying on was a patriotic and perhaps courageous gesture of defiance against accused terrorist mastermind Osama bin Laden. Claudette and Floyd Nelson, retirees from Mora, Minn., endured a 30-minute wait in bitter cold and passed through a metal detector to see the Liberty Bell in Philadelphia.

"It's telling that little slug over there that we're not afraid of him," said Claudette Nelson, 67. "He's not going to succeed. No way."