Sixteen suspected drug traffickers were arrested between Sunday and Thursday, some along Brazil's borders with Peru, Bolivia, Paraguay, and Argentina, and others in international transportation hubs such as Sao Paulo, the federal police said on Friday.
According to police reports, eight of the detainees are Serbian citizens, but their identities have not been revealed, AP reported.
The drug gang crackdown concluded a two-year operation that resulted in 35 arrests, the seizure of 1,370 pounds (620 kg) of cocaine, and the equivalent of 1.2 million dollars.
Former Brazilian drug czar Walter Maierovitch said that Serbian gangs have been operating in Brazil for at least a decade.
He added that Brazil has long been a transit point for cocaine coming from Colombia and Peru, which is sent on to Africa, Europe, and Asia.
The head of the US Southern Command said on Monday in Miami that the United States 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," General Douglas Fraser told 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 also pointed out that countries that do not have the means or will to fight major criminal enterprises within their borders could become hotspots where terrorist organizations are able to raise funds and organize.