They weren't there on vacation.

A crime gang allegedly led by Serbians was swept up by police in Brazil, shedding light on a growing problem for South America's largest nation -- foreign cartels increasingly using it as a corridor to export the continent's cocaine to Europe and elsewhere.

Security experts also said the existence of such criminal organizations across Latin America not only destabilizes the region, but could be dangerous for the U.S. and other nations because of suspicions that groups financing terror can use trafficking in the lawless areas to raise funds.

Sixteen suspected members of the Serbian gang were arrested between Sunday and Thursday across the country, federal police confirmed on Friday. Some were captured along Brazil's remote Amazon border near Peru, Bolivia, Paraguay and Argentina, and others in international transportation hubs such as Sao Paulo.

Brazilian police said that eight of those arrested were Serbian citizens and that the Serbian government has requested the extradition of the man suspected of leading the group.

Police in Brazil would not identify the suspects. But Serbia's justice minister, Snezana Malovic, said they include Goran Nesic and Dejan Stojanovic, who are on that country's most-wanted list. He said Serbia will seek their extradition.

Nesic was convicted of drug trafficking in Serbia and fled before he could serve his eight-year sentence, Malovic said. Stojanovic, also known as Keka, is wanted for robbery.

Serbian officials said they worked with Brazilian authorities and the U.S. Drug Enforcement Administration on the case. The DEA's office in Washington confirmed the agency assisted in the investigation, but provided no other details.

The crackdown concluded a two-year operation that resulted in 35 arrests, the seizure of 1,370 pounds (620 kilograms) of cocaine and the equivalent of $1.2 million.

Walter Maierovitch, Brazil's former drug czar, said Serbian gangs have been operating in Brazil for at least a decade, as are other international criminal organizations.

"Brazil is used as a two-way corridor by drug traffickers who receive export-quality drugs from Colombia and Peru and ship it out to Africa for transshipment to Europe and Asia," Maierovitch said. "Brazil is also the only country in Latin America that produces the chemicals needed to convert coca leaves into paste."

He added that Bolivia is a supplier of low-grade cocaine mainly for the Brazilian market, though U.S. officials have said foreign traffickers recently have set up more sophisticated labs there using Colombian technology.

Three Serbs were killed in Bolivia last year while serving as bodyguards for a local trafficker. Maierovitch said Brazil's economic boom is drawing more foreign criminals.

"As its economy grows stronger and attracts more and more investments, it is also attracting more attention from international drug traffickers who launder the profits they make from drugs in Brazil," he said.

One way to hide drug profits is buying up real estate, Maierovitch said, and Brazil has become one of the Western Hemisphere's hottest property markets. Police said a federal court ordered the seizure of the suspects' assets, which included 31 buildings, 15 luxury vehicles and three boats, with an estimated overall value of $16 million.

The head of U.S. military's Southern Command said Monday in Miami that the U.S. must recognize the increasing threat from transnational criminal organizations across Latin America.
"We have a key threat that we all need to focus on and that is transnational criminal organizations," Gen. Douglas Fraser said at a conference organized by the University of Miami's Center for Hemispheric Policy.

Fraser said the concern is not just drug trafficking but also weapons trade, money laundering and human trafficking.

He said countries that don't have the means or will to fight growing criminal enterprises within their borders could become spots where terrorist organizations can raise funds and organize.

The Associated Press contributed to this report.

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