Ecuador and Venezuela have moved troops to their borders with Colombia in an escalating row over the killing of a Farc rebel leader in Ecuador.
Venezuela ordered the deployment of 10 battalions
Ecuador and Venezuela have also both expelled Colombian diplomats.
Colombian troops entered Ecuador on Saturday in a raid that killed Colombian rebel leader Raul Reyes.
Colombia's foreign minister said he regretted that troops had to cross the border, but said it had been necessary "in the fight against terrorism".
"The Colombian government has never wanted to disrespect or violate the sovereignty or integrity of the sister republic of Ecuador," Fernando Araujo said.
A spokesman for Colombian President Alvaro Uribe said that during the raid, troops had found documents that provided information that "[Ecuadorean President Correa] has a relationship and commitments with Farc",
Police commander Gen Oscar Naranjo said one document showed Reyes had met Ecuador's minister of internal security and that they discussed Mr Correa's "interest in making official relations with the Farc".
On Sunday, Mr Correa announced the expulsion of Colombia's ambassador in Ecuador.
The Ecuadorean president also said he was calling for an immediate meeting of the Organization of American States and the Andean Community of Nations.
Spain and a number of Latin American countries including Mexico, Argentina and Brazil have offered to mediate in the dispute.
Speaking on his weekly television show, President Chavez said Venezuela's embassy in Bogota would close.
He lamented the killing of Reyes - whom he called a "good revolutionary" - when he spoke on his show, "Alo, Presidente".
Mr Chavez has been mediating with the Revolutionary Armed Forces of Colombia - or Farc - to secure the release of hostages the rebels hold, and six have so far been freed under this initiative.
Colombia's defence minister had described the death of Reyes as the "biggest blow so far" to Farc.
But Mr Chavez described the strike as "a cowardly murder, all of it coldly calculated".
He said Colombia had "invaded Ecuador, flagrantly violated Ecuador's sovereignty".
Mr Chavez addressed his defence minister, asking him to "move 10 battalions to the border with Colombia for me, immediately" - a deployment likely to involve several thousand soldiers.
"The air force should mobilise. We do not want war. But we are not going to let them... come and divide and weaken us."
Colombia's government has received billions of dollars in aid from Washington to fight the guerrillas - as the US, along with the EU, views Farc as a terrorist organisation.
Colombian troops have recently retaken control of areas previously held by rebel groups, but Farc retains a strong hold over Colombia's more remote regions.