President Clinton and Colombian President Andres Pastrana yesterday began a joint push for congressional approval of $1.3 billion in aid for the beleaguered South American nation, appealing for bipartisan support and early passage of the bulk of the money.

As Pastrana met with congressional leaders, Clinton told reporters that the U.S. goal is to help Colombians "gain some measure of control over their country again." The effort, he said, will be a "test run for the kind of challenges that my successors . . . will face" in the future, when drug traffickers, organized-crime groups and political terrorists may work together.

"I would be surprised if we don't have large numbers of Republicans and Democrats supporting this," Clinton said. "And I think we're going into this with our eyes wide open."

While Colombia tries to stem a flood of cocaine and heroin exports that supply 80 percent of the U.S. market, its government also is battling two leftist guerrilla armies and a right-wing paramilitary force--all of which derive income from taxing the drug trade. There is bipartisan agreement on the urgent need to address the narcotics trafficking, but congressional opinion is divided on how deeply and directly this country should become involved.

While Republicans have questioned the prowess of the Colombian military, some Democrats have expressed concern over the army's human rights record. In an interview yesterday with Washington Post reporters and editors, Pastrana acknowledged past human rights abuses. But he insisted that his administration had made major improvements by cashiering senior officers and imposing human rights regulations and polygraph exams on troops.

The administration's aid proposal consists of two segments: nearly $1 billion that could be approved in an emergency supplemental appropriation before spring, and about $300 million in the president's budget request for fiscal 2001. An additional $300 million already has been budgeted for the next two years. Nearly 80 percent of the aid would go for military supplies and training.

Pastrana, who arrived here Sunday for a three-day visit, said he was optimistic about ongoing peace talks with the country's largest guerrilla group, the Revolutionary Armed Forces of Colombia, or FARC. But outside a "peace zone" from which government forces have withdrawn in the south of the country, he said, "complete war" continues with the rebels.

Pastrana said the most important military element in the aid package is training and equipment for a 5,000-member rapid deployment force to bolster the anti-narcotics efforts of the Colombian police. The U.S. military already has trained an initial battalion of 1,000 soldiers. Additional training and equipment are needed for the Colombian navy and air force, he said, to block the primary drug export routes in the air and along Colombia's rivers.