BOGOTA, COLOMBIA, NOV. 24 -- President Virgilio Barco said today suspected billionaire drug baron Jorge Ochoa Vasquez could not be extradited to the United States to face cocaine smuggling charges under current law and must first serve a 20-month jail sentence in Colombia.

"According to our laws, Mr. Ochoa must first serve the sentence pending against him in Cartagena. In the meanwhile, we will continue to study the possibility of extraditing him," Barco said in a short interview with the private news program "Noticiero Nacional," broadcast on government-controlled television tonight.

"At the moment, however, there is no legal mechanism in force here to enable us to extradite any Colombian to any other country," Barco said.

Ochoa was arrested as the result of a "routine traffic check," officials said. Because he was driving a car registered to someone else, he was taken to police headquarters where police realized they had picked up an alleged drug kingpin and cattle smuggler.

Ochoa allegedly is one of three top leaders of the Medellin cocaine cartel, which U.S. officials say is responsible for 80 percent of the cocaine smuggled into the United States.

Supreme Court Justice Julio Salgado said that under international law, Colombia could not extradite Ochoa because its extradition treaty with the United States was declared illegal June 25 by the Colombian high court.

But Barco said the matter would be studied.

The U.S. Embassy in Bogota refused to comment on the Ochoa situation.

In Miami, Ana Barnett, assistant to U.S. Attorney Leon Kellner, said the U.S. government has petitioned the Colombian government for Ochoa's extradition three times.

In 1986, a Colombian Customs Court released Ochoa on $11,500 bail in a case involving the illegal importation of bulls despite an extradition order for him to stand trial in the United States. Barco said Ochoa now must serve 20 months in a Colombian prison for violating import laws.