Colombia said that Daniel "El Loco" Barrera, alleged to be the country's last major drug lord, had been caught in neighboring Venezuela in an international sting led from Washington.
"The last of the great capos has fallen," President Juan Manuel Santos announced on national television, adding that the US Central Intelligence Agency (CIA) and Britain's MI6 intelligence service had provided support.
Barrera, whose outfit is estimated to have sent more than 900 tons of cocaine to the United States and Europe, was caught in the Venezuelan city of San Cristobal, said Santos, adding that the drug lord had criminal ties to FARC (Revolutionary Armed Forces of Colombia) rebels and paramilitaries.
"This is perhaps the most important capture of recent times," the president said, thanking the Venezuelan government for its help.
Venezuelan Interior Minister Tareck El Aissami confirmed the arrest on Twitter, calling it a "major coup" for his country and adding that "images" and "details of the operation" would be released Wednesday.
Venezuela's foreign ministry said Barrera was captured "after an intelligence operation carried out by Venezuelan authorities," without mentioning any foreign involvement.
Venezuelan President Hugo Chavez has long had rocky relations with Washington and regularly accuses the United States of trying to undermine his leftist government.
Santos said the operation "was led from Washington," adding that the head of Colombia's national police, General Jose Leon Riano, had helped direct it from the US capital.
Speaking from Washington, Leon Riano told the Caracol television network that authorities had tracked Barrera for four months before arresting him at a phone booth in San Cristobal.
He added that the operation had been orchestrated from Washington because it required "special technical support." US authorities could not immediately be reached for comment.
In 2010 the US Treasury had named Barrera a "special designated narcotics trafficker," saying he faced criminal charges in New York and was allied with the FARC, Latin America's longest-running insurgency.
In the 1980s and early 1990s Colombian cartels dominated the American drug trade, but a US-supported government crackdown has left local gangs in increasing disarray.
In 2011, 252 of Bogota's 1,632 registered homicides -- 15.4 percent -- were linked to drugs, according to official figures.
The regional cocaine trade, however, is still alive and well: in 2011 Colombia was the world's largest cocaine producer, according to a United Nations report, though neighboring Peru is expected to soon overtake it.
Colombian criminal gangs as well as leftist guerrillas and right-wing paramilitary groups sell the cocaine to Mexican criminal syndicates, who then smuggle it into the United States and Europe.
Colombia recently agreed to relaunch peace talks with the leftist FARC after a decade-long hiatus, raising hopes of resolving Latin America's last major armed conflict.