NEW YORK – Some malls around the world have been scrambling to add security guards to look for suspicious people following a deadly attack on a shopping center in Nairobi over the weekend. But for other malls, it has been business as usual.

The mixed reactions by malls across the globe isn’t unusual in an industry whose security efforts vary from unarmed guards in most U.S. shopping centers to metal detectors and bag searches in such places as Israel to main entrances that resemble airport security lines in India.

The disparity offers a glimpse of why any moves following the Nairobi incident to increase mall security in countries that have less strict procedures aren’t likely to last. The industry continues to struggle with how to keep shoppers safe without scaring them away.

“No one wants, when you go shopping, to be strip-searched, to be interviewed in a room by a security guard,” said Simon Bennett, director of the University of Leicester’s Civil Safety and Security Unit in England. “That might be acceptable in aviation, but it is not in commercial retail.”

Security concerns come after 12 to 15 militants from the Somali Islamic extremist group al-Shabab, wielding grenades, took control of the upscale Westgate Mall in Nairobi. Terrorists held Kenya security forces for four days, killing at least 67 civilians and government troops and injuring 175 others.

The Kenyan government said Tuesday that the attackers had been defeated, with several suspects killed or arrested. On Wednesday, FBI agents began fingerprint, DNA and ballistic analysis to help figure out the identities and nationalities of the victims and the gunmen.

In the aftermath of the attack, security was tight at the Junction Mall in Nairobi. Two of three entry gates were locked shut. Cars were searched more carefully than usual, with guards looking in glove compartments. Two armed soldiers were stationed inside the mall, and mall security guards who search patrons with metal detector wands at entry points said the soldiers had been deployed after the Westgate attack.

In the United States, the International Council of Shopping Centers, a trade group of shopping centers representing about one-third of global retail space, said the Department of Homeland Security is reaching out to corporate security at all malls.

At the same time, the group said, some of the malls in the U.S. and South Africa are beefing up private security personnel, while others are bringing in more off duty police officers. Mall of America, the biggest U.S. shopping center, added extra uniformed security officers and stepped up other measures, but officials at the Bloomington, Minnesota-based mall declined to elaborate.

“We will . . . remain vigilant, as we always do in similar situations,” said Dan Jasper, a mall spokesman.

In general, U.S. malls focus on reacting to a shooting more than preventing one. They depend on private security personnel, most of whom don’t carry guns, though they do work with local police. And while they are trained to look for suspicious behavior and report that to authorities, security personnel are discouraged from intervening.

“Shoppers at this point perhaps don’t have an appetite for extraordinary measures,” said Kenneth Hamilton, executive vice president of IPC International, the largest U.S. provider of shopping center security.

Indeed, heightened security hasn’t been welcomed in American malls. The International Council of Shopping Centers spent $2 million to develop a terrorism training program after the September 2001 terrorist attacks, but surveys conducted by the group following the attacks show that people don’t want to be subjected to metal detectors and bag searches at malls.

Jeff Wohl, 45, of Atlanta, said Tuesday that while he is horrified by the Nairobi attack, he doesn’t want to go through bag checks at malls. “Any public gathering . . . can become a target,” he said. “But you have to live your life.”

U.S. malls have made changes to their security strategies following attacks. A shooting on Dec. 5, 2007, at the Westroads Mall in Omaha, Nebraska, for instance, was an impetus for malls to change how they deal with shooters themselves. After a 19-year-old man shot and killed eight people and injured five others before taking his own life, malls began working with Homeland Security on a plan to have the first responders from the police department enter the building to stop the shooter and free those who are trapped rather than wait for backup.

Many mall operators now also have evacuation drills once or twice a year that focus on lockdown scenarios. A growing number of malls also use cameras that scan license plates in parking lots. And many malls use technology that enables them to share 3-D blueprints of their layout with law enforcement.

The reaction to attacks can be more muted in other parts of the world.

In China and Hong Kong, malls are operating normally following the Nairobi attack, typically monitored by closed-circuit cameras and with unarmed private security guards stationed throughout.

“We review our security system and conduct emergency drills regularly to ensure that we are ready to respond to any breach of security swiftly and effectively,” said Elizabeth Kok, retail portfolio director at Swire Properties Ltd., which operates three upscale malls in Hong Kong.

At the busy PPR mall in downtown Shanghai, a security guard who gave only his surname, Zhang, said he saw no need for any heightened security: “I can say that the possibility of the same kind of thing happening here is almost zero. Everyone knows that China prohibits guns, and Shanghai is such a safe city.”

In Australia, a similar sentiment was expressed. Tobias Feakin, senior analyst for national security at the Australian Strategic Policy Institute, said the country’s malls would likely make a point of ensuring their security staff operate on a heightened level of awareness in light of the attacks. But given the relatively low risk of terrorism in Australia, he said, it is unlikely they will make major security changes.

Meanwhile, Michael Green, chief executive of the British Council of Shopping Centers, a shopping center trade group, said that they work closely with police forces including Scotland Yard and would respond to warnings with appropriate measures. But they don’t want to turn malls into prisons.

“We have to make them welcoming,” he said.