Accused narcotics trafficker Carlos Lehder Rivas sat comfortably on a wooden chair in a jungle clearing, brushing his shoulder-length hair away from his face for the television cameraman. In the background, a guard in fatigues paced with an automatic rifle.

Millions of Colombians on national television were watching this interview with a notorious fugitive. "Cocaine and marijuana," Lehder declared, "have become an arm of struggle against American imperialism. We have the same responsibility in this -- he who takes up a rifle, he who plants coca, he who goes to the public plaza and denounces imperialism."

The audacity of Lehder's clandestine meeting with a Spanish film crew and the subsequent televising of it here were undeniable signs of the trouble facing Colombian and U.S. authorities in their campaign against this nation's drug traffic.

Nine months after declaring a "war without quarter" to break up the multi-billion-dollar empires of cocaine traffickers, President Belisario Betancur remains in a stalemate with adversaries whose power sometimes seems to rival his own. "It reminds me of Nazi Germany in the 1930s, when criminal elements took over," said outgoing U.S. Ambassador Lewis Tambs.

Since last May, when Betancur responded to the assassination of justice minister Rodrigo Lara Bonilla by declaring a state of siege, the chief of the trafficking organizations, collectively known in Colombia as "the mafia," have been driven from public prominence to hideouts in the jungle or abroad. Arrests of narcotics suspects have nearly tripled and seizures of cocaine jumped from 5,400 pounds in 1983 to 47,000 pounds last year.

Neverthless, Colombia remains a country saturated by drugs and their accompanying corruption. Most of South America's cocaine continues to be processed by Colombian groups and passed through the country on its way to Europe and the United States, officials say. Following a bumper crop of coca leaves in the growing regions of Peru and Bolivia, a recent State Department report said, the international market is flooded.

The reach of this Colombian mafia remains astounding. Last month, more than 2,500 pounds of cocaine with a street value of about $600 million was discovered in Miami aboard a Boeing 747 jet of the Colombian national airline, Avianca. In December, a Colombian diplomat in Spain and functionaries of the presidential palace in Bogota were arrested in connection with an attempt to smuggle cocaine in a diplomatic valise.

Perhaps most seriously, the accused leaders of the Colombian mafia have eluded the government's dragnets, established new hideouts in the jungles, and mounted an increasingly violent campaign to defend their business. "We have passed the point of no return," Lehder declared in his television appearance.

"Lara Bonilla, Tambs and Betancur united to conspire against the interests of this country," he added. "Lara Bonilla was executed by the people."

Betancur and Tambs have also been targets. A powerful bomb reportedly was discovered on a train that Betancur was due to take on a trip in the interior last month. Tambs, a high-profile advocate of antidrug efforts, left the country with his family in December because of threats on his life and returned briefly last month only to take formal leave of his post.

After a car bomb exploded outside the U.S. Embassy here in November, about 17 percent of personnel were evacuated from the country along with their families, Tambs said. Armored vans were flown in for transport and streets around the embassy compound and the ambassador's residence were closed to traffic and blocked with concrete-filled drums.

The bomb attacks have continued. A string of blasts, mostly near U.S. businesses, was reported early last month in the commercial center of Medellin. Two weeks ago, another bomb killed a guard and caused extensive damage at the Baranquilla office of the Colombian-American Center, a U.S.-backed cultural foundation.

In telephone calls and letters, presumed Colombian traffickers repeatedly have promised to kill Americans in retaliation for the extradition of Colombian drug suspects to the United States. The threat, Tambs said in an interview here, "is very real;" the traffickers have "a total disdain for innocent human life."

Colombian officials and enforcement officials say the escalating violence is at least in part a sign of progress. "It's no secret that the retaliation level has increased," said one. "But that's because we're hurting them."

Government officials contend that the crackdown, including sweeps by the Army and confiscation of suspected traffickers' property, has eliminated the huge industrial complexes that once processed cocaine in remote rural and jungle areas. They say traffickers have been forced to return to mobile, small-scale processing operations, to divert shipments of cocaine through other South American countries, and to spend most of their time in hiding or abroad.

Tolerated and even admired by many Colombians, accused traffickers such as Lehder and Pablo Escobar had lived on huge private estates, dabbled with soccer teams or other community projects, and openly worked in politics.

Escobar, once described as the Robin Hood of Medellin after he financed lighting for a local soccer stadium, was elected as an alternate delegate to Congress in 1982 on the ticket of the Liberal Party, Colombia's largest political organization. Lehder, an unblushing admirer of Adolf Hitler, built a disco, founded his own political group, the National Latin Civic Movement, and published a newspaper.

By his own account, Lehder left Colombia for seven months after the government finally launched its crackdown. Escobar has also been abroad, officials say, and remains in hiding. However, even after Lehder's return and daring media appearances, security forces have been unable to catch him or shut down his business.

"It's more difficult than you would suppose to get these people," said Nazly Lozano, the vice minister of justice. "They have great financial resources, more than we do. And they have a lot of people who protect them -- because a lot of people have done well with them."

Some officials say a few of the dozen major Colombian trafficking organizations may even have increased their defensive strength, possibly through alliances with dissident factions of Colombian leftist guerrilla organizations that have refused to accept recent cease-fire settlements with the government.

Tambs and former U.N. ambassador Jeane Kirkpatrick have suggested that the cooperation between drug traffickers and revolutionary movements may be extensive, involving the governments of Cuba and Nicaragua. Colombian officials, however, say they do not believe that there are formal connections between the Colombian mafia and either guerrilla organizations or foreign governments.

Whatever the source of their military strength, the major trafficking organizations have clearly focused their counteroffensive on U.S. backing for the Colombian crackdown and the extraditions of Colombians to the United States.

The president has now approved seven extraditions, and the first four suspects were delivered to U.S. authorities in January. The response was the string of bombings and Lehder's dramatic statement: "I have returned to prevent the extradition of nationals to the imperial state. A political, economic and social battle against extradition is beginning to organize."