Bogota, Colombia ? Venezuela and Ecuador sought Monday to make Colombia pay a high price for killing a leftist rebel leader in the Ecuadorean jungle – expelling its diplomats, ordering troops to the border and cracking down on trade across the border.

But Colombia quickly struck back, revealing what it said were incriminating documents seized from the rebel camp that suggest its neighbors have been secretly supporting the leftist rebels’ deadly insurgency.

And in a tit-for-tat move, Venezuela later displayed the laptop of a slain drug trafficker, which it said contained information implicating Colombia’s national police chief in the cocaine trade.

Ecuadorean President Rafael Correa piled on the pressure, saying Colombia’s killing of the rebel leader Raul Reyes Saturday had scuttled talks between his government and the guerrillas to free 12 rebel-held hostages, including French-Colombian politician Ingrid Betancourt and three U.S. defense contractors.

“I’m sorry to tell you that the conversation were pretty advanced to free 12 hostages, including Ingrid Betancourt, in Ecuador,” said Correa in a televised address. “All of this was frustrated by the war-mongering, authoritarian hands” of the Colombian government.

Colombia’s national police chief stood by its attack that killed Reyes, and said that documents recovered from his laptop showed Venezuela’s leftist government recently paid $300 million to the rebels, among other financial and political ties that date back years, and that high-level meetings have been held between rebels and Ecuadorean officials.

And this shocker: Colombia says some documents suggest the rebels have bought and sold uranium.

“When they mention negotiations for 50 kilos of uranium this means that the FARC are taking big steps in the world of terrorism to become a global aggressor. We’re not talking of domestic guerrilla but transnational terrorism,” Gen. Oscar Naranjo said at an explosive news conference.

Naranjo didn’t give any details on when, where or from whom the uranium was allegedly bought. He provided no proof of the payment and wouldn’t release copies of the documents, which he said are “tremendously revelatory” and are being examined with the help of U.S. experts.

Both Venezuela and Ecuador dismissed his allegations as lies. They expelled Colombia’s top diplomats and recalled their own. Correa planned to visit five Latin American countries starting today to defend his decision to break off diplomatic relations, accusing Colombia of being an enemy of peace and lying about the nature of the raid.

Colombia said military commandos, tracking Reyes through an informant, were fired upon from Ecuadorean territory. But Correa said Colombia deliberately carried out the strike beyond its borders, and that the rebels were “bombed and massacred as they slept, using precision technology.”

Both Venezuela and Ecuador also began reinforcing their borders, mobilizing troops and tanks as Chavez warned that another Colombian attack could spark a wider South American war.

Maintaining trade with Colombia, essential to Venezuela’s economy, is one of many factors weighing against outright war. But the bellicose rhetoric has worried Latin American leaders. The presidents of Chile, Mexico and Brazil offered to mediate, and an emergency session of the Organization of American States was scheduled for today in Washington.