OLYMPICS

ritzy beach neighborhood of Leblon shut down streets for several hours last week after discovery of a suspicious bag that turned out to contain only clothes.

“I never felt like this about terrorism before. I only worried about street crime,” said Fernanda Rocha, a pharmacist in Rio. “I have no idea how to avoid terrorists if they come.”

Despite Brazilians’ easygoing attitude, better suited for a street party than an urban lockdown, Ford said there have been major improvements since the 2014 World Cup. Training exercises with U.S. and other foreign militaries to deal with chemical, biological and nuclear attacks have become more frequent. A joint-intelligence center has been created for the games, allowing intelligence services from around the world to share information and investigate threats as they emerge.

Precisely because of Rio’s reputation for criminality, elite police units are more battle-tested than their counterparts in major U.S. cities.

“They’re used to carrying bigger and stronger guns than we are,” said Bobby Chacon, a retired FBI agent who makes his home in Rio and spent a year running security at the 2004 Games in Athens.

There are expected to be 85,000 military personnel and police fanning out across the city, double the number on the streets in London in 2012. While most will be concentrated at sporting venues, tourist landmarks will also be heavily patrolled.

“They have the police in place and trained to stop a large-scale, coordinated attack,” Chacon said. “But there’s plenty of opportunities to cause harm, and they shouldn’t take anything for granted.”