By Patrick Markey

SANTO DOMINGO, March 6 (Reuters) - Ecuador announced a rare capture of Colombian guerrillas on Thursday as Latin American leaders gathered for a summit that will be dominated by a regional crisis over a cross-border raid by Colombia.

"In an operation by the armed forces, five presumed guerrillas were found. FARC guerrillas," Security Minister Gustavo Larrea said about the captures in an Amazonian region on Ecuador's side of the border with Colombia.

Ecuador, which Colombia has accused of warning the Marxist rebels about planned raids against them, arrested and extradited a top FARC leader known as Simon Trinidad in January 2004, but such captures have been rare recently.

Colombia ignited regional tensions when it raided Ecuador's territory last weekend and killed more than 20 rebels from the Revolutionary Armed Forces of Colombia, or FARC.

Venezuela and Ecuador have moved troops to their borders with Colombia, a conservative-led U.S. ally in a region that has been shifting to the political left, but all sides say they do not want to go to war.

Venezuela has threatened to limit trade and investment ties with Bogota. Nicaragua joined Venezuela and Ecuador on Thursday in cutting off diplomatic relations with Colombia.

Colombia complains that its neighbors Ecuador and Venezuela -- both oil-exporting nations run by leftists -- have protected FARC guerrillas whose group has killed thousands of Colombians over four decades.

Colombian President Alvaro Uribe, who is popular at home because of his hard line against the guerrillas, said documents and photos found on computers at the rebel camp bombed at the weekend proved FARC ties with Ecuador and Venezuela.

Venezuelan President Hugo Chavez retorts he has only had contact with the FARC to persuade them to release hostages and seek peace.

CHAVEZ LEADS CONDEMNATION

Chavez has led the region in general condemnation of Colombia's violation of Ecuador's sovereignty and the strongly anti-U.S. leader says the United States is militarizing Colombia in order to attack Venezuela.

The people of Latin America have to decide between "the road to war that Uribe wants, backed by Bush, leading us to more violence, more war, more death, more war between us, or the road to peace," Chavez said after landing in the Dominican Republic for Friday's summit.

The United States has backed Colombia, its closest South American ally and recipient of billions of dollars in U.S. aid for fighting guerrillas and the cocaine trade.

The leaders of Argentina, Colombia, Ecuador, Mexico, and other Latin American countries were also arriving in the Caribbean nation on Thursday for the Rio Group summit that had been planned long before the crisis.

Nicaraguan President Daniel Ortega, an ex-guerrilla whose country is in a territorial dispute with Colombia over small islands, said he was breaking off relations "in solidarity" with Ecuadorean President Rafael Correa, who visited Nicaragua on Thursday before heading for Panama.

"We are breaking with the terrorist politics that Alvaro Uribe's government is employing," Ortega said.

Mexico has been relatively quiet about the crisis but may be drawn into the fray as Ecuador's government said it was investigating whether Mexicans were among the more than 20 dead in the FARC camp.

Ecuador's Correa hopes to win an explicit condemnation of Colombia at Friday's summit.

"We want clear answers tomorrow," Correa said in Panama on Thursday, his sixth stop on a tour of the region to lobby against Uribe.

(Writing by Fiona Ortiz; editing by Stuart Grudgings)

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