The Organization of American States will hold an emergency meeting Tuesday in an attempt to peacefully resolve a dispute involving Colombia, Ecuador and Venezuela, which have sent troops to their borders.

Ecuador's President Rafael Correa, right, speaks during a news conference in Quito, 03 Mar 2008

Ecuador's President Rafael Correa says he feels betrayed by Colombia's government for the attack against Colombian FARC rebels encamped in Ecuador.

He also says the raid derailed talks between his government and FARC to secure the release of 12 hostages, including former Colombian presidential candidate Ingrid Betancourt.

Ecuadorian officials also reject Colombian claims that Quito has links to the Marxist rebels.

Colombian Vice President Francisco Santos said Tuesday material found on the computer of FARC's deputy commander showed the group was trying to buy radioactive material to use in so-called dirty bombs.

Colombian officials also say their forces found documents during Saturday's raid showing that Venezuelan President Hugo Chavez paid $300 million to support FARC rebels in Colombia.

Venezuelan officials reject the claim.

Venezuela has ordered the expulsion of Colombia's ambassador and other diplomats from Caracas. Ecuador has also broken relations with Colombia.

Both the Ecuadorean and Venezuelan presidents have ordered troops to their countries' borders with Colombia.

Colombia's government apologized for the raid, which killed 21 people, but said it was a necessary part of its decades-long military struggle with FARC rebels.

U.S. State Department spokesman Tom Casey voiced support for Colombia's efforts to respond to threats from the FARC, which the United States considers a terrorist organization. Casey appealed for a diplomatic solution to the dispute between Colombia and Ecuador, and called on Venezuela to stay out of it.

Some information for this report was provided by AFP and Reuters.