An international police operation involving Serbia and Montenegro has nabbed Balkan "cocaine king" Darko Saric, who had been on the run for more than four years.
Saric is alleged to be the mastermind behind a cocaine trafficking network set up between 2007 and 2009 with links across Europe and South America.
Feeling the noose tightening around him, Saric contacted Serbian authorities through a lawyer on February 24 and offered an unconditional surrender, Serbia's Justice Minister Nikola Selakovic told reporters on Tuesday.
Saric, 43, moved between several South America prior to the arrest, Selakovic said.
"He circulated among four countries in South America, where our intelligence services located him," the minister said.
He refused to reveal further details while the investigation is ongoing, including which countries Saric had frequented or where he was first picked up.
Saric was at some stage transferred from South America to authorities in Montenegro, before being moved to Belgrade on Tuesday morning.
"He is now being interrogated by an investigative judge of a special court for organised crime," Serbia's organised crime prosecutor Miljko Radisavljevic said.
"He is accused of trafficking at least 5.7 tonnes of cocaine and money laundering at least 22 million euros ($A34 million)," he added.
Saric is already being tried for drug trafficking in absentia, along with 19 members of his organisation.
