Ecuador has urged the Organization of American States (OAS) to condemn Colombia for violating its territory.
Ecuador said an apology would not suffice for the Colombian incursion
Colombian forces killed senior Farc rebel commander Raul Reyes and 16 others inside Ecuador on Saturday.
At an emergency session of the OAS, Foreign Minister Maria Isabel Salvador said an apology would not suffice and demanded a full investigation.
Colombia's ambassador to the OAS, Camilo Ospina, denied there had been an incursion.
He said the Colombian army had fired at the Farc (Revolutionary Armed Forces of Colombia) camp from helicopters in Colombian airspace.
He reiterated that documents found at the camp linked both Ecuador and Venezuela to the Colombian rebel group.
The US representative, Robert Manzanares, supported Colombia's action, saying Farc was a threat to the whole region.
The OAS agreed to convene a meeting of the group's foreign ministers, and recommended the creation of a fact-finding mission to investigate events surrounding the incident.
Earlier, Colombian President Alvaro Uribe said his government would ask the International Criminal Court to bring genocide charges against his Venezuelan counterpart, Hugo Chavez.
He said this was based on the discovery of a laptop at the rebel camp, which he said contained files indicating that Venezuela had given $300m (£151m) to the left-wing group.
Colombian officials have also accused the rebels of trying to buy 50kg of uranium to make a radioactive "dirty bomb".
Both Venezuela and Ecuador have poured scorn on the claims, broken off ties with Bogota and moved troops to the Colombian border.
Although insisting his military would target Farc "wherever they are", Mr Uribe said he would not allow Colombia to be drawn into open war.
"Colombia has never been a country to go to war with its neighbours," he said. "We are not mobilising troops, nor advancing toward war."
The military defeat of Farc has been a cornerstone of Mr Uribe's administration since he came to power in 2002.
Colombia has received billions of dollars in aid to fight the guerrillas from the US administration which, along with the EU, views Farc as a terrorist organisation.