Nicaragua broke off diplomatic ties with Colombia Thursday, widening a Latin American crisis over a raid by Colombia on a rebel camp inside Ecuador last Saturday.
Venezuela and Ecuador have also cut relations with Colombia and sent troops to their frontiers with the U.S.-backed state in reaction to the cross-border raid, which prompted leftist allies in Latin America to line up against Colombia.
And an Ecuador government spokeswoman said the military captured five suspected Colombian guerrillas on the Ecuadorean side of the border between the two countries.
The announcement comes during a week of Colombian complaints that Ecuador has protected FARC guerrillas.
Nicaraguan President Daniel Ortega, an ex-guerrilla whose country is in a territorial dispute with Colombia, said he was breaking off relations "in solidarity" with Ecuadorean President Rafael Correa, who was visiting Managua.
Ortega's move strengthened the leftist alliance that has formed around Ecuador and Venezuela and left their neighbor, Colombian President Alvaro Uribe, increasingly isolated and under pressure to apologize.
"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.
Summit to address crisis
The leaders of Colombia and Ecuador and other presidents from the region were heading Thursday to a summit of Latin American leaders in the Dominican Republic where the Andean crisis would be center stage.
Ecuador's Correa hopes to win an explicit condemnation there against Colombia, which has the backing of President Bush and receives billions of dollars of U.S. aid for fighting guerrillas and the cocaine trade.
"We have to make decisions ... to clearly condemn the Colombian aggression and make sure this government never again dares to attack a brother country," Correa said.
Earlier this week, the United States helped block moves at the Organization of American States for a formal condemnation of Colombia. Instead, the diplomatic body noted that Colombia had broken international law by violating Ecuador's sovereignty.
Rice backs attack on rebels
U.S. Secretary of State Condoleezza Rice said Thursday that the United States wants to see a diplomatic solution. The United States offered unqualified support to Colombia in the dispute, in contrast to almost every other country in the hemisphere.
"I do hope there will be a diplomatic outcome to this," Rice said in Belgium. "The situation shows that everyone needs to be vigilant about the use of border areas by terrorist organizations."
At the summit, Uribe hopes to persuade leaders he had to act against the rebel FARC because Ecuador allows the guerrillas to take refuge there.
Uribe, who is popular at home because of his hard line against the FARC, also accuses Anti-U.S. Venezuelan President Hugo Chavez of supporting the guerrillas, who have killed and kidnapped thousands in their four decades of insurgency.
Colombia says documents and photos found on computers at the bombed rebel camp prove Ecuador and Colombia were supporting the Marxist rebels of the Revolutionary Armed Forces of Colombia, or FARC.
Chavez is also expected to travel to the Dominican Republic summit.
"Never before has any country in Latin America reached the point of taking a pre-emptive attack doctrine or the doctrine of pursuing your internal enemies in every corner of the globe," he said Thursday in his latest criticism of Colombia.
Economic havoc feared
Earlier Thursday, Venezuela began blocking billions of dollars in Colombian investments and imports in response to the Colombian military attack. Ordered by Chavez, the move threatens economic havoc on both sides of the Venezuela-Colombia border.
In Venezuela, Chavez predicted a sharp fall in the $6 billion annual Colombia-Venezuela trade: "That's coming down."
"We aren't interested in Colombian investments here," Chavez said, standing beside Correa. "Of the Colombian businesses that are here in Venezuela, we could nationalize some."
Chavez called the attack by Colombia's U.S.-allied government a "war crime."
He said Venezuela will search for products from other countries to replace those from Colombia. Noting that Colombia traditionally supplies food to Venezuela, he said now "we can't depend on them, not even for a grain of rice."
Though Venezuelan officials express confidence they will quickly find replacements for Colombian goods, government critics say the move is bound to worsen shortages of basic foods from milk to chicken that were an annoyance in Venezuela well before a dispute that has ballooned into one of South America's most serious diplomatic crises in years.
Venezuela and Ecuador have each sent thousands of soldiers to their borders with Colombia.