KEY POINTS:
President George W Bush has firmly backed Colombia in the deteriorating crisis in Latin America and criticised Venezuela's Government for making "provocative manoeuvres".
Washington is frantically trying to defuse the rising regional tensions.
Hundreds of Venezuelan troops have moved towards the border with Colombia, where trade was slowing amid heightening tension over Colombia's cross-border strike on a rebel base in Ecuador.
The Organisation of American States prepared for an emergency session to try to calm one of the region's worst political showdowns in years, pitting US-backed Colombia against Venezuela's leftist President Hugo Chavez and his allies.
Colombian and Ecuadorean officials traded accusations in the United Nations and the International Criminal Court.
The escalation of tensions was triggered over the weekend when Colombian troops crossed the border with Ecuador and killed Raul Reyes, a top commander of the Colombian Farc rebels, who had set up a camp there. Colombia has received some US$5 billion ($6.4 billion) in US aid to fight drugs and leftist rebels since 2000.
So what really happened?
The Colombians say they first bombed a rebel camp on their own side of the border. They claim that rebels hiding across the border in Ecuador fired on them, so they crossed the border to fight back.
The Ecuadorean President, Rafael Correa, called that account an outright lie. "It was a massacre," he said. The Colombian troops were backed by military planes, suggesting the raid was pre-ordained.
When Ecuadorean troops reached the rebel camp they found the rebels were killed "in their pyjamas". The rebels were "bombed and massacred as they slept, using precision technology".
Colombian military sources seemed to corroborate this by revealing that US intelligence helped target the rebels by disclosing that the rebel's deputy leader, Raul Reyes, was using a satellite telephone, whose signal could be pinpointed.
What's at the heart of the dispute?
In Colombia, a left-wing group of rebels called Farc - the Revolutionary Armed Forces of Colombia - has been fighting the Government for four decades. Their aim is a fairer wealth distribution in the country, which has a huge divide between rich and poor. But they finance their armed struggle by trading in cocaine and political kidnapping. Their base is in the remote rural regions of the country but they also take shelter in Ecuador and Venezuela which each have a porous border over 1600km long with Colombia.
What's the position of the three leaders?
Colombia is ruled by a right-wing populist, Alvaro Uribe, a Harvard-educated lawyer who is an ally of the Bush administration. Since coming to power in Colombia in 2002, he has maintained a hard-line policy against the Farc rebels, who killed his father during a kidnap attempt. Washington has poured billions of dollars in American aid to support the Colombian military.
The president in Ecuador is a young left-wing economist, Raphael Correa. He has not minced his words in the current crisis. Colombia has "a foul and lying government that doesn't want peace". In Venezuela, the charismatic leftist president Chavez, backed by his country's vast oil reserves, is attempting to direct the continent away from the influence of Washington. He called Reyes a "good revolutionary".
What were the rebels doing?
The Colombians claim they have captured the computer of Reyes, who was the rebels' main interlocutor with foreign governments. It reveals, they claim, growing ties between rebels and Venezuela and Ecuador. One document, it was said, showed Chavez had provided US$300 million to the Farc. In another letter, the rebels offered military assistance to Venezuela in the event of a US attack. A third, it was claimed, showed the rebels were in negotiations for 50kg of uranium to build a dirty bomb. Venezuela and Ecuador poured scorn on the Colombian claims.
Why is the US involved?
As much as 90 per cent of all cocaine on US streets comes from Colombia. Since 2000, the US has spent billions giving Colombian forces training and equipment to hunt down drug traffickers and eradicate coca crops.
Since 2002, the Bush administration has conceded that some aid is now being spent to tackle the insurgency, even though there is evidence that all sides in Colombia are involved in drug trafficking. Venezuelan officials insist they have information about links between drug traffickers and top Colombian officials. The Colombian Government has also played into American paranoia about the "war on terror", characterising Farc not as an armed struggle to bring political change in a highly segregated society but as an arm of international terrorism.
What do other countries in the region think?
The big regional heavyweight, Brazil, which has mainly cordial relations with the three presidents involved, has demanded Colombia apologise to Ecuador. Brazil fears the conflict is beginning to destabilise regional relations. The president of Argentina is to visit Venezuela. Peru has urged restraint. Mexico and Chile have offered to mediate.
Could there be full-scale war?
Certainly the rhetoric is supercharged. Chavez said: "If it occurs to you to do this in Venezuela, President Uribe, I'll send some Sukhois" - the 24 warplanes he recently bought from Russia.
The President of Ecuador has said: "This is not a bilateral problem, it's a regional problem ... should this set a precedent, Latin America will become another Middle East."
But there is little appetite for armed conflict. The economic costs would be too high.
The signs are of a climb-down. Colombia has indicated that it will not send more troops to its borders. And Washington, while backing Colombia's right to defend itself, has irged dialogue.
LATIN LEADERS
HUGO CHAVEZ
Charismatic commando turned politician who has used Venezuela's oil bonanza to start a "Bolivarian revolution". Critics call him a divisive firebrand; supporters say he is a champion of the poor.
ALVARO URIBE
Staunch US ally and right-wing populist who has won two commanding election victories in Colombia. Uribe's hatred for Farc guerrillas stems from the death of his father.
RAPHAEL CORREA
Young left-wing economist and former minister who clinched a surprise win at the last Ecuadorean elections. Part of the so-called "pink tide" of socialist leaders in Latin America.
- INDEPENDENT
