PARIS — Darko Saric, described as being among the most feared and wanted drug traffickers in the Balkans, was arrested in Serbia on Tuesday and charged with smuggling more than five tons of cocaine and laundering at least $30 million as leader of an elaborate drug ring that stretched from South America to western Europe, the Serbian authorities said.

Serbian law enforcement officials said Mr. Saric ran an extensive drug trafficking operation, smuggling cocaine from countries like Colombia, Argentina and Uruguay to western Europe via the Balkans, Italy and Slovenia. They said Mr. Saric and his gang laundered part of the proceeds through properties and businesses, including restaurants.

Mr. Saric, 44, arrived in Belgrade, the Serbian capital, on Tuesday after traveling through Montenegro from an unspecified Latin American country, according to B92, an independent Serbian broadcaster. The authorities said they would not identify the country, for fear of tipping off Mr. Saric’s associates, 18 of whom remain at large. So far, 11 people accused of being his fellow gang members have been arrested and are on trial in Belgrade.

Officials said Mr. Saric had been on the run since October 2009, when a shipment of almost three tons of cocaine that he was smuggling was confiscated near the Uruguayan coast as part of an operation, called “Balkan Warrior,” that included agents from the Drug Enforcement Administration in the United States.