War of words
Colombia later said it had found documents in the rebel camp indicating that Hugo Chavez, the Venezuelan president, had given the Farc group $300m.
It said other documents indicated Reyes had ties to an official allied with Rafael Correa, the Ecuadorean president.
Venezuela and Ecuador angrily denied the allegations, with Francisco Suescum, the Ecuadorian ambassador withdrawn from Bogota, saying: "This is a lie. Neither the government of Ecuador or President Correa has ever had such an attitude."
Correa himself said there was "no justification" for the raid, and appeared to reject a Colombian apology for the incursion.
"The government of Ecuador energetically rejects these accusations which cynically add to the hostile attitude shown in the recent violation of our sovereignty," his government said.
Correa said on Monday that he planned to travel to Venezuela on Wednesday for talks with Chavez on the crisis.
Al Jazeera's Teresa Bo, reporting from Colombian capital Bogota, said there had been no Farc response to the raid so far, although many Colombians feared revenge attacks against military targets or against hostages being held by the group.
For now though, Alvaro Uribe, Colombia's president, is enjoying strong support from his people for his tough tactics against the Farc, Bo said.
Uribe appeared to be seeking international support for his government's actions too, with Bogota saying it would present its case to the United Nations and the Organisation of American States.
The US, which supports Colombia's fight against the Farc rebels, urged the countries to resolve the ongoing spat through diplomatic means.
"I don't think anybody, at this point, ought to be talking about military action," Tom Casey, the US state department's deputy spokesman, said on Monday.
Brazil also urged calm on all sides but condemned Colombia's raid on Saturday as a "territorial violation".
Betancourt contact killed
Meanwhile France, which has been hoping to negotiate the release of French-Colombian politician Ingrid Betancourt, said on Monday that Reyes had been their contact during delicate negotiations for her release.
"It is bad news that the man we were talking to, with whom we had contacts, has been killed," Bernard Kouchner, the French foreign minister, told French radio on Monday.
Betancourt has been held by the Farc, along with about 40 other foreign hostages, for more than six years, along with hundreds of Colombian hostages.
Following the release of four Farc hostages last week - in a move brokered by Chavez with the rebel group - one of the freed hostages said Betancourt was gravely ill and had not much longer to live.