Venezuela moved troops toward Colombia and turned away cargo trucks at border crossings on Tuesday as tensions mounted over Colombia's strike on a leftist rebel base in Ecuador.

Ecuador also reinforced its border with more troops and sought international condemnation of the attack, which killed a top commander of Colombia's main rebel group and 22 other guerrillas.

Colombia said documents found at the rebel base showed the Revolutionary Armed Forces of Colombia were trying to acquire radioactive material that could be used for dirty bombs — and that Venezuela and Ecuador had deepening ties with the FARC. Venezuelan and Ecuador said Colombia was lying.

The Organization of American States held an emergency meeting in Washington to try to calm one of the region's worst political showdowns in years. Colombia apologized for the attack, but Ecuador wasn't satisfied, calling for OAS to investigate.

Colombian President Alvaro Uribe said the International Criminal Court should try Venezuelan President Hugo Chavez for "genocide" for allegedly financing FARC, listed as a terrorist organization by the U.S. and the European Union. He cited documents in laptops Colombia says were recovered at the jungle camp that apparently refer to a $300 million Venezuelan payment.

Despite troop movements and saber rattling, Uribe said he would not allow his nation to be drawn into war.

"Colombia has never been a country to go to war with its neighbors," Uribe said. "We are not mobilizing troops, nor advancing toward war."

President Bush accused Chavez of "provocative maneuvers" and said the U.S. stands by the conservative Colombian government, its key ally in a region dominated by leftists. Bush said he personally delivered this message to Uribe during a phone call earlier Tuesday.

Colombia has received some $5 billion in U.S. aid to counter the drug trade and battle leftist guerrillas since 2000.

The attack on Ecuadorean territory reflected Colombia's long-held frustration over the ability of rebels to take refuge across poorly patrolled patrols.

Uribe said he has provided Chavez with precise information on the location of FARC camps in Venezuela — one of which, he alleged, was home to rebel leader Ivan Marquez.

Chavez warned Uribe that any strike on Venezuelan soil could provoke war. But his forces would be outnumbered: Venezuela and Ecuador have about 172,000 active military troops between them. Colombia's U.S.-equipped, trained and advised military has more than 250,000.

Colombia said documents in Reyes' laptop also indicate that Ecuador' internal security minister met recently with a FARC envoy to discuss deepening relations with Ecuador, and even replacing military officers who might oppose that.

Ecuadorean President Rafael Correa angrily denied the allegations, calling Uribe a "bold-faced liar." He said his military had "captured" 47 rebel camps in Ecuador since he took office last year.

"And they ask me if we are accomplices of the FARC?" Correa said during a visit to Peru, part of a regional tour seeking to rally other Latin American leaders against Colombia.

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 was sending 3,200 troops to its border.

Venezuela also was closing its border to imports and exports, said Agriculture Minister Elias Jaua. Trade between the two countries is worth $5 billion a year, most of it Colombian exports sorely needed by Venezuelans already suffering milk and meat shortages. But Juau said Venezuela would look to other countries for necessary imports.

"We cannot depend for anything at all on a country that's in a war posture against its neighboring countries," Jaua said.

Venezuelan soldiers were turning away Colombian tractor-trailer trucks at the frontier bridge in the city of Cucuta, where 70 percent of cross-border trade occurs.

Extra Venezuelan National Guard troops were stationed at the Cucuta crossing, where people entering Venezuela were being subject to more stringent searches.

Some 300 vehicles, including trucks carrying food, shoes, ceramics and other products, were stuck waiting for permission to enter Venezuela, said Leonardo Mendez, a spokesman for a Colombian cargo transport association.

Fuel distribution fell sharply in the Venezuelan border state of Tachira, said Isidoro Teres, who runs a Venezuelan business chamber the border town of Urena.

In Ecuador, where trade with Colombia totals $1.8 billion annually, commerce and migration continued freely on Tuesday, said Carlos Lopez, Ecuador's undersecretary of immigration.

The biggest losers from the killing of Raul Reyes, who was the official spokesman for the FARC, could be hostages that might have been swapped for jailed guerrillas.

Reyes was a key negotiator with France for the release of former Colombian presidential candidate Ingrid Betancourt, a dual French national whose case has been a priority for French President Nicolas Sarzozy.

The FARC said in a communique that Reyes died "completing a mission to arrange, through President Chavez, a meeting with President Sarkozy" aimed at securing Betancourt's release.

Correa claimed his government also was working toward a hostage swap. "All of this was frustrated by the war-mongering, authoritarian hands" of the Colombian government," he said.

Publicly, there had been little indication of progress toward a swap of 40 hostages, including three U.S. military contractors, for hundreds of jailed guerrillas.

Several Latin American leftist leaders have suggested the U.S. was intimately involved in executing the raid that killed Reyes. The Colombian military has said U.S. satellite intelligence and communications intercepts have put the FARC on the defensive.

On Tuesday, the U.S. Southern Command would neither confirm or deny American military participation. "We do provide intelligence support to partner nations but I can't get into details on operations," spokesman Jose Ruiz told the AP from Miami.

At a U.N. disarmament meeting in Geneva, Colombian Vice President Francisco Santos claimed the FARC were trying to acquire radioactive material that could be used to make "dirty bombs."

Without providing details, he said the evidence was found two computers found with Reyes. Colombian officials said Monday that investigators found documents suggesting the rebels had bought and sold uranium.