Venezuela and Ecuador took their growing conflict with Colombia to the diplomatic front, seeking international condemnation of Colombia's deadly assault on a rebel base in Ecuador.

The two countries tightened their borders and were deploying thousands of troops, while Colombia on Tuesday pointed to documents found in a slain rebel leader's laptop that it called proof of stunning links between the leftist guerrillas and Venezuelan leader Hugo Chavez.

Ecuador rejected a Colombian apology for the cross-border strike as insufficient, and sought to rally opposition during an emergency meeting of the Organization of American States, convened in Washington to help defuse one of South America's most volatile crises in years. Venezuela's justice minister declared that war "has already begun."

At Venezuela's border with Colombia, National Guard troops turned back Colombian cargo trucks under orders from Caracas.

Ecuadorean President Rafael Correa began a six-nation tour in Peru and Brazil, calling Colombian President Alvaro Uribe a liar who "wanted war." Correa warned that if the attack goes unpunished, "the region will be in danger, because the next victim could be Peru, it could be Brazil, Venezuela, Bolivia, any one of our countries."

At the moment, it's mostly a war of words, and other nations have tried to keep it that way, although many said Colombia was wrong to send troops into Ecuador. The military assault on Saturday killed 24 guerrillas, including Colombian rebel spokesman Raul Reyes, who was engaged in hostage talks with Venezuela, France and other countries.

President Bush backed Colombia and accused Chavez of "provocative maneuvers."

Uribe said Chavez should be prosecuted before the International Criminal Court for allegedly financing the Revolutionary Armed Forces of Colombia, or FARC. Uribe said documents found in a laptop seized in Reyes' camp showed Venezuela recently made a US$300 million payment to the rebels.

Venezuela dismissed the allegations as lies and Foreign Minister Nicolas Maduro said the idea of prosecuting Chavez was "laughable." Justice Minister Ramon Rodiguez Chacin said the hand of Washington was behind Colombia's actions, declaring: "Our enemy is the empire."

Colombia also accused the rebels of trying to make a radioactive dirty bomb, although the documents it shared with reporters don't support that allegation, indicating instead that the rebels discussed the possibility of buying uranium to resell at a profit.

In Brazil, Correa suggested late Tuesday that the Colombian raid was carried out to prevent the liberation of rebel-held hostages.

He offered no proof, but said he agreed with speculation that Colombia targeted Reyes "to prevent a deal for the liberation of the hostages from going forward."

The FARC freed four hostages last week, and Chavez had pledged to try to win freedom for others including French-Colombian politician Ingrid Betancourt.

The rebels said Tuesday that Reyes died "completing a mission to arrange, through President Chavez, a meeting with (French) President (Nicolas) Sarkozy" aimed at securing Betancourt's release.

In Washington, Ecuadorean Foreign Minister Maria Isabel Salvador said Colombia's apology wasn't enough, demanding that the OAS condemn the incursion, appoint a commission to investigate it and call an urgent meeting of the region's foreign ministers in the next week.

Colombia's attack on the camp 1.8 kilometers (just over a mile) inside Ecuador reflected its frustration over the ability of rebels to take refuge across poorly patrolled borders.

Uribe said he would not allow his nation to be drawn into war.

Venezuela was sending about 9,000 soldiers — 10 battalions — to the border region as a "preventive" measure, retired Gen. Alberto Muller Rojas, a former top Chavez aide, told The Associated Press. Ecuador said it sent 3,200 troops to the border on Monday.

Venezuela's agriculture minister, Elias Jaua, said Venezuela had closed the border — which sees annual trade worth roughly US$5 billion — to imports and exports.

Leonardo Mendez, a spokesman for a Colombian cargo transport association, said some 300 vehicles, including trucks carrying food, shoes, ceramics and other products, were stuck at one major border crossing.

Despite the shrill rhetoric from the Andean governments, in several border towns there was little sign of tension apart from the turning away of trucks by Venezuelan border guards.

Contenting themselves by calling Chavez "crazy", Colombian truckers lounged in the shade drinking beer and saying they hope the crisis won't persist long.

When the border is open, each day some 8,500 metric tons (9,400 tons) of merchandise cross between Colombia and Venezuela in both directions, said Jaime Sorzano, head of the cargo transport association. "In the past, we've had episodes, problems, but like this crisis no. It's unprecedented," he said.