The US, however, said it backed Colombia's efforts to respond to the "threat and challenge" from the Farc movement.
Tom Casey, a US state department deputy spokesman, said: "We consider the Farc - the Revolutionary Armed Forces of Colombia - to be a terrorist organisation. We support the government of Colombia in its efforts to respond to that threat and challenge."
Regional governments said they would help to resolve the standoff with Brazil cautioning that the tensions were destabilising regional ties.
France, which has worked to free rebel-held hostages, also called for restraint on all sides.
The Colombian government had accused Rafael Correa, the Ecuadorian president, of having ties with Farc, the largest Colombian rebel group.
A spokesman for Alvaro Uribe, the Colombian president, said documents found in the wake of the attack on the camp inside Ecuador yielded information "that ... Correa has a relationship and commitments with Farc".
Colombian police said the documents were apparently written by Reyes.
Correa had expelled Colombia's ambassador and withdrawn his own envoy from Bogota on Sunday in protest against what he said was an intentional violation of his nation's sovereignty.
|Chavez warned that Colombia's actions could |
start a war in South America [AFP]
Hugo Chavez, the Venezuelan leader, had its embassy in Colombia to be shut and diplomatic staff withdrawn, warning that Colombia's actions could spark a war in South America.
"We do not want war but we are not going to let them ... come and divide and weaken us," Chavez said on his weekly TV show.
The Venezuelan leader said he was ordering 10 battalions - about 6,000 troops - to the border with Colombia.
Chavez called Uribe a "criminal", saying: "Not only is he a liar, a mafia boss, a paramilitary who leads a narco-government and leads a government that is a lackey of the United States ... he leads a band of criminals from his palace."
On Saturday, Colombia's military announced its troops had killed Reyes, during an attack on a jungle camp in Ecuador, a blow to the group behind Latin America's oldest uprising.
Juan Manuel Santos, the Colombian defence minister, said commandos, tracking Reyes through an informant, first bombed a camp on the Colombian side of the Ecuadorean border.
He said the troops came under fire from across the border and encountered Reyes' body when they overran that camp.
"It was a massacre,'' said Correa, who accused Colombia of lying and said some rebels were shot in the back.
Uribe has complained before that Farc fighters take refuge in frontier areas, though neighbours say his troops are not doing enough to prevent the conflict spilling across the borders.