Even before the Westgate shopping mall attack in Kenya in 2013, shopping malls worldwide have been on heightened alert for a terrorist attack. The Westgate incident may have punctuated the efforts, but when it comes to guaranteeing security in stores, the best that can be said is: It’s complicated.

In the U.S., federal agencies like the Department of Homeland Security and the Federal Bureau of Investigation regularly coordinate efforts with state and local officials. They issue alerts following threats or actual attacks, strategically deploy antiterrorism units and conduct drills. Earlier this year, for example, New York’s police and fire departments conducted a joint training exercise in Brooklyn, which was the city’s largest to date. Retailers and mall operators also participate, and some, such as the Mall of America, even have their own antiterrorism task forces.

In Europe, the relationships among police, government and local authorities can be difficult to untangle. Obtaining a clear set of security recommendations from anyone is a challenge, since officials and retail associations argue that the success of such measures depends on keeping them secret.

In France, the target of repeated large-scale terrorist attacks since last year, the national security alert system known as Vigipirate has been on “attack alert” in the Paris region since the Charlie Hebdo shootings in January 2015. It rose to the same level in the Alpes-Maritimes region after the Nice attack on July 14.

That has implied extra security patrols for public transport, tourist hot spots, department stores and places of worship. In addition, tougher measures — such as random bag checks — were added to the already stringent security instructions in force in public places.

These are relayed at several levels. The senior defense and security official at the Ministry of the Economy, Finance and Employment forwards directives to the National Council of Shopping Centers. The Interior Ministry deals with commercial property firms, and the police, with individual retailers.

Dorian Lamarre, director of institutional and external relations at the CNCC, noted that many shopping centers and department stores have gone a step further than required by placing two security guards at each entrance and checking the bags of every person who enters.

“Since January 2015, the security level at shopping centers has been reinforced and more particularly since November 2015,” he said. “In terms of improvements, discussions are under way on how to tackle security,” Lamarre added, noting that he was being intentionally vague about the particulars.

The extra measures have placed a heavy burden on retailers, who have sharply increased spending on private security. Yet some argue the efforts are insufficient. In April, a program on French TV channel France 2 showed a journalist entering a shopping center and several department stores with a gun in his bag.

Daniel Rémy, a security expert with 40 years’ experience, believes French firms rely too much on the government and do not spend enough on protecting themselves. He said this was risky, pointing to accusations of security failures in the wake of the Nice attack, in which 84 people were killed.

“Most of the measures that are taken are just for show and are not really efficient,” he alleged.

He recommended implementing simple preventive and dissuasive steps at every level of the organization and hiring professional security guards.

“You need trained, qualified, motivated bodyguards who are not afraid of risk — but they are paid two to three times more. So the real problem is cost, and the fact that nobody wants to pay the price,” he said.

In Japan, the government’s Cabinet Office sets out detailed instructions for companies to deal with critical incidents threatening business continuity, including earthquakes. They were most recently updated in 2013.

“In Japan, good business continuity practices have already been secured to some degree and have been proven to be effective in practice, and some of these practices in Japan are more advanced than in other countries. Based on these experiences, enterprises should further improve their efforts,” the office said.

In Germany, which suffered four attacks in one week in July — including one at the Olympia shopping center in Munich in which a lone shooter killed nine people and injured 27 others — the police interventions in the face of the attacks were widely perceived as adequate. Citizens praised the local police.

The German security system is highly complex and authorities evade comment on how it works, claiming that discretion is part of the strength of German security operations.

Terrorism and threats from abroad fall into the competence of the foreign intelligence service Bundesnachrichtendienst that is subordinated to the Foreign Office. National security, on the other hand, is part of the Interior Ministry, which administers several intelligence agencies and the federal police. Additionally, each of Germany’s 16 federal states has a state police force.

In the case of the attacks, interventions were mostly carried out by the respective state police. Faced with terrorist threats, shootings or hostage cases, they can request assistance from neighboring states and the federal police, as in the case of the Munich attacks. The military rarely comes into action nationally.

Chancellor Angela Merkel has stood by Germany’s policy of welcoming refugees, even though three of the recent attacks were committed by asylum-seekers. She has since called for a thorough review of security measures.

“The first priority is that, where there are gaps, we must take action as we have done in the past to make clear that we’re doing everything humanly possible to ensure security in [our country],” she said.

She outlined a nine-point plan to increase security throughout the nation, including deciphering web chatter, improving security responses to the attacks and an early warning system for the radicalization of refugees.

ECE, a retail group that manages 196 shopping centers in Europe, including Munich’s Olympia center, said security staff was preventively increased in all centers, and they remain in close contact with local police forces to evaluate security conditions individually.

“The fundamental hazard assessment for Germany has not changed,” said a spokesman for the Federal Criminal Police Office. “Germany, like other European states, has been in the focus of Islamic terrorists for a long time. The risk of assaults by small groups and radicalized mavericks also generally has to be reckoned with. But at this moment, there are no specific indications for ongoing terrorist plots.”

By contrast, the U.K. estimates the current threat level for international terrorism to be “severe.” Metropolitan Police Commissioner Sir Bernard Hogan-Howe said this means an attack is highly likely.

“You could say it is a case of when, not if,” he wrote recently in the Mail on Sunday newspaper. He detailed how, in the wake of the November attacks in Paris, Britain has increased the number of specially trained and equipped officers who would confront heavily armed terrorists.

“Although we can’t talk about the tactics of how many armed officers we have on the street at any one time, our capacity to confront the most terrible of threats is increasing threefold,” Hogan-Howe said.

It didn’t take long for a threat to appear. Shortly after the publication of Hogan-Howe’s letter, antiterrorist firearms officers were deployed to patrol the streets and shopping malls of London as the city woke up on Aug. 3 to the murder of a woman in Russell Square by a man wielding a knife.

Hogan-Howe immediately launched “Operation Hercules,” a security response program that provides for an extra 600 armed officers — who are pulled from various parts of England — to protect London against the threat of terrorist attacks.

Amid recent attacks, detective chief superintendent Scott Wilson, the U.K.’s national police coordinator for protective security, tried to sound reassuring.

“Counterterrorism officers are working day in, day out with the retail sector to strengthen our resilience,” Wilson said. “Staff working in shops, bars and restaurants across the country are attending detailed briefings on what they can do to improve their protective security and — should the worst happen — what action they should take to help protect themselves and their customers.”