Sao Paulo state police take part in a simulated hostage situation during a security exercise on July 21 ahead of the 2016 Rio Olympics. (Roosevelt Cassio/Reuters)

Here in Brazil, it’s not unusual to hear bloodcurdling screams in the airport; they’re usually just the sounds of teens playfully chasing each other through the terminal. It’s also not unusual to see suitcases sitting near the boarding gates, left by travelers who wandered off to get coffee.

In many ways, Brazilians live in a pre-9/11 world. Although they might be used to heavily armed criminals and police in their cities, they are largely unfamiliar with international terrorism.

But this month, with the Olympic Games looming, a series of incidents has raised even the most violence-numbed eyebrows here. On July 15, Brazilian authorities deported a French-Algerian physics professor who in 2012 had been convicted in France of providing logistical advice to terrorists.

Then, a Brazilian group pledged allegiance to the Islamic State via the messaging app Telegram. And in the past few days, a dozen sympathizers of the Islamic State have been arrested after they allegedly discussed a possible attack on the Games, which will begin here Aug. 5.

South America’s largest country has had virtually no experience with the kind of attacks by Islamist extremists that have rattled European and U.S. cities. Many people treat the terror threat with lightheartedness. For the Carnival celebrations in February, they might dress up as Osama bin Laden and make edgy jokes about bombings.

Brazilian security forces have arrested 10 people suspected of belonging to a group supporting Islamic State for allegedly preparing acts of terrorism during next month's Olympics in Rio. (Reuters)

But reality has begun to set in.

At a news conference last week, the secretary of security for the state of Rio de Janeiro, José Mariano Beltrame, told reporters that an anti-terrorism center with 50 police officers was functioning in Brasília, the capital, and that at least 80,000 security personnel would be in the streets of Rio during the Games, which is double the number deployed in London in 2012.

“We are ready, the plans are finished,” he added.

When asked whether he was concerned about the possibility of a terrorist attack during the Games, which are expected to attract as many as 500,000 visitors, Beltrame responded: “Of course we are worried. But Brazil is a low-threat country.”

Brazil does rank very low on assessments such as the Global Terrorism Index, published by the New York-based Institute for Economics and Peace. On its list of countries affected by terrorism, the United States ranks 35th, while Brazil ranks 74th.

Still, this country is not free of possible threats. The justice minister last week announced the operation against a dozen Brazilian men who had allegedly talked about training in martial arts and buying firearms for a possible attack on the Games. The minister, Alexandre de Moraes, described the men as “amateurs” who expressed support for Islamic State but had never trained with the group in Iraq or Syria.

In response to the terror threat, authorities have conducted security exercises and rolled out some new security procedures. On a recent Saturday, an underground metro station in Rio — the stop fans will use to attend basketball and cycling events — closed so police in riot gear could storm the cars in a training exercise.

A few days later, Brazilian travelers arrived at Rio’s airports to find massive lines and confusion as authorities introduced heightened security screenings — including pat-downs and luggage checks — that were previously only required for international flights.

Last week, the government launched a campaign equivalent to the “If You See Something, Say Something” campaign in the United States. Its mantra is “Fica Ligado,” which in Rio de Janeiro slang means, “Pay Attention,” and the accompanying posters show a woman tugging on the sleeve of a police officer as she points to a lone backpack.

Some experts are concerned these measures come too late. “You don’t want to be completely altering some security fundamentals at the last minute,” said Patrick Skinner, director of special projects for the Soufan Group and a former CIA case officer specializing in counterterrorism. “You want to roll that out in stages and see how it goes and work it out, because even in the greatest bureaucracy, there are going to be a lot of glitches.”

He added that fixing security problems two weeks before the Olympics is “a recipe for disaster.”

Is Rio ready?

Other cities that have hosted the Olympics have had ample experience with terrorism. Far-left militants set off bombs in Athens just a few months before the Games there in 2004, and London had experienced an attack on its subway system by Islamist extremists seven years before the 2012 Olympics. Russia was also recovering from domestic bomb attacks in the run-up to the Sochi Winter Olympics in 2014.

As with most Summer Olympics, the geography of the 2016 Rio Games is “sprawling” and “there will be no shortage of targets,” because “what terrorists are looking for is crowds, from bars to beaches,” Skinner noted.

While some experts questioned Brazil’s capacity to cope with a terrorist attack, others said the country might do fine. Skinner noted that, “We have seen it before where it looks like the Olympic security is a mess and then it turns out okay because they throw everything they can at it.”

Security secretary Beltrame emphasized that in recent years, Brazil has hosted a series of major international events with few security problems, from the Rio+20 climate change conference to the World Cup.

But even though they may not fret about terrorism on a day-to-day basis, many Brazilians fear that their country is ill-prepared for its possibility.

“I wasn’t worried before the Nice attacks,” said 28-year-old Marilia Domingues, a medical resident in Rio, referring to the recent massacre of 84 people by a Tunisian-born man who drove a truck into a crowded promenade in the French city.

“But now, I think about how crowded the sidewalks here are during the World Cup or Carnival or New Year’s, how every bar and every restaurant is full, and I can’t help but think, how hard could it be to drive a truck into a crowd in Rio?”