BUENOS AIRES, Argentina (AP) _ U.S. drug czar Barry McCaffrey rejected the possibility of American military intervention in Colombia, insisting Friday that the government in Bogota must confront the drug trade.

``There will be no U.S. intervention, not even a discussion at all,'' McCaffrey said in Argentina, the final stop of a four-nation tour of South America. ``It is certainly the viewpoint of those of us in the United States that the solution can only come from the Colombian leadership.''

Several visits to Bogota by high-ranking U.S. officials, coupled with talk of increased U.S. aid and rising concerns in Washington over the Colombia's situation, have fueled speculation in Colombia of an imminent U.S. intervention.

McCaffrey, the director of the U.S. Office of National Drug Control Policy, has recently urged the United States to boost its anti-narcotics spending in the Andean region to $1 billion, with nearly a third of the funds going to Colombia.

He said along his weeklong tour that Colombia's security problem is worse than it was four years ago.

Fighting between leftist rebels and right-wing paramilitary groups, both with ties to the drug trade, has displaced more than 1 million Colombians. Heroin production is increasing and ``enormous'' drug resources are going now to leftist guerrillas, McCaffrey said.

``Cocaine production has doubled in three years, heroin production has grown from zero to 6 metric tons a year, and they are producing hundreds of millions of dollars that go to armed insurgent groups,'' he said.

Just what role the U.S. government should play has been sharply debated in Washington, where Republicans argue American aid has been slow to arrive, hampering the war on drugs in Colombia. Critics worry that by stepping up aid, the United States could get drawn into bloody civil war.

McCaffrey said at every stop of his tour that the United States must remain committed to helping Colombia.

Earlier on his tour, McCaffrey said cocaine consumption in the United States has declined 70 percent over the last decade, prompting traffickers to seek new markets in Europe and Asia. He said drug traders were forging new routes through South America, particularly through Brazil and Argentina.

McCaffrey's weeklong tour precedes a November summit of 34 nations from the Americas aimed at developing a program of cooperation against drugs.