Colombian police say they have smashed a drug-trafficking network that was exporting several tonnes of cocaine to the US each month.
More than 30 suspects were arrested in co-ordinated raids across the country.
They are accused of belonging to the Urabenos, a powerful cartel founded by former right-wing paramilitaries.
Colombia's Defence Minister, Rodrigo Rivera, said the operation was a major success in the fight against cocaine trafficking.
"With this operation we have affected the entire structure of this organisation dedicated to producing and exporting drugs," he said.
The arrests were made with the help of the US Drug Enforcement Agency.
The Urabenos are one of dozens of violent drugs cartels that emerged in Colombia following the demobilisation of the paramilitary Self-Defence Forces of Colombia (AUC) in 1996.
It is led by two brothers who took over following the arrest last year of the drug lord Daniel Rendon Herrera, also known as Don Mario.
Based in the north-western region of Uraba, from where the group gets its name, the Urabenos have embarked on a national expansion with the apparent aim of becoming the biggest drug cartel in Colombia, says the BBC's Jeremy McDermott in Bogota.
They now dominate trafficking routes along Colombia's Caribbean Coast, and this latest network was seeking to take over routes in the eastern plains and into Venezuela, our correspondent adds.