Neighbors Fear Fallout of Aid To Colombians
Pres Clinton's upcoming visit to Colombia comes as country's neighbors fear increased US military aid will step up fighting that could push coca growing, drug trafficking, refugees and conflict across their borders; Colombian conflict has already led to guerilla incursions into Panama and Venezuela, rebel influence among Indian dissidents in Ecuador, and new Colombian plantings of coca and poppies in Peru; regional leaders fear impact of $1.3 billion in additional US aid over next two years to train and equip anti-narcotics brigade; Sec Madeleine Albright, visiting region, hears warnings from nervous Ecuadorean and Brazilian leaders; photo of Pres Gustavo Noboa of Ecuador and Pres Andres Pastrana of Colombia; map (M)