BOGOTA, Colombia - On the eve of President Clinton's visit to Colombia, neighboring countries are growing increasingly worried about a planned U.S.-backed drug war - and some are even preparing for a possible spillover by sending troops to the borders.
The offensive - to be carried out by Colombian soldiers trained by Green Berets and other U.S. special forces - is expected to displace thousands of people.
The rebels, who earn millions of dollars from a drug-protection racket, have vowed to fight the Colombian troops, who are to be deployed on U.S.-donated combat helicopters. Eighty-three U.S. troops are currently training soldiers from a new 1,000-member anti-narcotics battalion at a military base in southern Colombia. A total of 3,000 Colombian soldiers are to be deployed in the offensive, expected to begin next year.
Ecuador, which lies to the south of Colombia and is within sight of Colombian cocaine-producing plantations, has doubled its border forces to 4,000 troops, the Ecuadorean Defense Ministry said.
The U.N. High Commissioner for Refugees has sent delegates to the Ecuador border region and is considering building a camp to hold some 5,000 Colombian refugees.
On Colombia's northwestern frontier with Panama, fighting between rebels and government troops has crossed the untamed border region in recent years, and thousands of Colombian refugees have crossed into Panama.
Panamanian officials fear the situation will only get worse when the anti-drug war heats up.
''Although we are not in the position to say whether or not this plan should be carried out, I personally believe it would be better if it was not,'' Panamanian Interior Minister Winston Spadafora said Thursday.
Spadafora said he has requested aid from the United Nations to prepare for spillover.
On Colombia's eastern border, Brazil has reportedly begun beefing up security along its 960-mile frontier with Colombia, amid fears the anti-drug offensive could send Colombian guerrillas fleeing into Brazil or prompt coca-growers to move into its vast Amazon jungle.
Brazil is also worried that any defoliants used to combat Colombian drug production could damage its rain forest, a Brazilian Foreign Ministry official said Thursday in Sao Paulo.
Meanwhile, relations between Colombia and Venezuela, which borders northeastern Colombia, have hit a sour note over the planned anti-drug offensive and Colombian officials' accusations that the Venezuelan army has been funneling weapons to Colombian rebels - allegations the Venezuelans deny.
After Venezuela's Foreign Minister Jose Vicente Rangel said in a radio interview last week that violence in Colombia threatened neighboring countries, Colombian Foreign Minister Guillermo Fernandez shot back that Rangel was showing ''a lack of respect for Colombia.''
Peruvian President Alberto Fujimori also warned last week the anti-drug offensive could threaten regional stability.
Tensions and fears persist despite efforts to quell them by both Colombian and U.S. officials, including Secretary of State Madeleine Albright and Clinton's new envoy to Colombia, Anne Patterson.
Patterson has called the concerns ''a little exaggerated,'' but said Washington would do what it could to help remedy any problems.
Colombia has also sought to calm the fears, with Fernandez offering assurances in an interview Friday that the government plans major social programs in drug-producing areas to help people displaced by the fighting and to discourage them from fleeing into neighboring countries.
Demand is growing in Colombia for officials to cool the situation.
''The Colombian conflict is becoming more of a concern for the security of our five neighbors,'' the Bogota daily El Espectador noted in an editorial Saturday. ''It's not easy being the nucleus of a conflict, but if that is our luck, we must learn to manage the situation.''
Colombia's widening conflict is expected to be among the top agenda items at the South American Presidents Summit, to be held in Brasilia on Thursday, the day after Clinton's visit to Colombia. Clinton is not attending that summit.
On Monday, three leading human rights groups criticized the Clinton administration for aiding the Colombian military, saying President Andres Pastrana's government has failed to meet any of the human rights criteria set by Congress.
Clinton waived several of the conditions and released $1.3 billion in mostly anti-drug aid for Colombia last week. The conditions were aimed at overcoming military abuses and bringing human rights violators to justice.
Amnesty International, Human Rights Watch and the Washington Office on Latin America (WOLA) all assailed Clinton's decision.