Colombia

Ecuador and Venezuela said Sunday that they were moving thousands of troops to Colombia's borders, a day after Colombian forces killed a leftist rebel leader in Ecuadorean territory. Bogota later charged that high officials in Ecuador met recently with the slain rebel, Raul Reyes, to accommodate the guerrillas' presence there.

President Alvaro Uribe appears to have taken a calculated risk in ordering his armed forces to invade Ecuador to kill a top rebel leader, deciding to risk the ire of his southern neighbor to inflict a major loss in a decades-long war. Tensions continued to mount Monday after the clandestine operation in which Colombian soldiers and aircraft entered Ecuador to kill Raul Reyes, the nom de guerre of the No. 2 commander in Colombia's largest rebel group, known by its Spanish initials, FARC.

An increasingly isolated Colombia came under heavy criticism from its neighbors at an emergency Organization of American States session Tuesday for killing a top Colombian rebel leader in Ecuador last weekend. A sense of crisis has enveloped the region as diplomats worked to avoid an armed conflict that could be devastating to a continent that has successfully transitioned into a mostly democratic region after the military juntas and "dirty wars" of the 1970s and 1980s.

Even as relations remained tense between Colombia and Venezuela, there were signs Wednesday that the Andean region's most serious crisis in recent years might be easing. In Washington, the Organization of American States passed a consensus resolution that used mutually acceptable language to rebuke Colombia for having violated Ecuadorean sovereignty Saturday in a raid that killed a high-ranking rebel leader and 16 others.

Even at a rally where the placards, chants and speeches carried a distinctly anti-government flavor, Colombians on Thursday backed President Alvaro Uribe after his soldiers' risky incursion into Ecuador to kill a leftist rebel leader. The incursion Saturday brought reproval from the Organization of American States and prompted neighbors Ecuador and Venezuela to mass troops at their borders and cut diplomatic ties.

A Latin American border crisis triggered by the Colombian military's incursion into Ecuador to kill a rebel leader was apparently resolved Friday when Ecuadorean President Rafael Correa accepted his Colombian counterpart's apology and promise not to repeat the transgression.

Former President Fidel Castro said it was "stupid" to think Cubans were involved with Colombian rebels whose camp was bombed in a cross-border raid in Ecuador early this month. In a statement released Saturday, the 81-year-old Castro dismissed allegations reportedly being investigated by Mexican authorities that Cubans were linked to the Revolutionary Armed Forces of Colombia, or FARC.

Re "Anxiety in the Andes," editorial, March 16 The editorial correctly calls on the Organization of American States to play a larger role in the recent crisis among the Andean nations. The U.S. is right to defer to the OAS and focus its efforts on promoting a free-trade agreement with Colombia. Only through open trade can such countries improve economic prosperity and enjoy continued declining support for leftist guerrillas and their drug-trading partners. A greater concern lies with poorer countries such as Bolivia and Ecuador, where poverty leads citizens to support populist leaders.

Colombia's Defense Ministry said Wednesday night that it had recovered uranium that officials have alleged leftist rebels might have acquired to make a "dirty bomb." In a statement, the ministry said informants last week brought military intelligence officers a chemical sample, which tests found to be "degraded uranium." On Wednesday night, officials were at the site a few miles south of Bogota to recover the source of the sample, a cache weighing up to 66 pounds.

U.S. officials expressed concern Thursday over charges that the Colombian rebel group the FARC was seeking ingredients for a radioactive "dirty bomb," but said the material discovered this week poses little danger. Even as they downplayed the threat from about 66 pounds of degraded or depleted uranium Colombian officials said they found and had linked to FARC guerrillas, the U.S. officials said they were not dismissing Bogota's claim that the rebel group intended to procure deadly weapons.