CARACAS, Venezuela — Interpol, the international police agency, said yesterday that computer files seized by Colombia’s army in a raid on a rebel camp belonged to a top guerrilla commander and had not been modified or forged.

The announcement, made at a news conference in the Colombian capital by Interpol’s secretary general, Ronald Noble, was a blow to President Chavez of Venezuela, who sought to discredit the files because they contain information linking his government with a rebel force fighting to topple President Uribe of Colombia.

“No one can ever question whether or not the Colombian government tampered with the seized FARC computers,” Mr. Noble said, referring to the Revolutionary Armed Forces of Colombia by the rebel group’s Spanish initials. “We are absolutely certain that the computer exhibits that our experts examined came from a FARC terrorist camp.”

The files contain e-mails and documents that show how Venezuela’s populist leader had formed such a tight bond with guerrilla commanders that his key lieutenants had offered help in obtaining sophisticated weaponry such as surface-to-air missiles while delivering lighter arms. The files also document links between the FARC and Ecuador’s president, Rafael Correa, a close ally of Chavez.

At a news conference in Caracas yesterday, Mr. Chavez questioned Interpol’s impartiality, called the report “ridiculous” and mocked Mr. Noble as “ignoble” and a “gringo policeman,” referring to his American citizenship.

Mr. Chavez also said Colombia committed an international crime by striking the rebel camp where the computers were found. “He came to applaud assassins,” Mr. Chavez said of Mr. Noble and the Colombian officials who attended his news conference. “How sad. How indignant this is.”

Mr. Chavez has consistently denied arming or funding the FARC.

In Paris, where she was traveling with Mr. Correa, the Ecuadoran Foreign Minister, Maria Isabel Salvador, said the “chain of custody” of the documents had not been guaranteed, so the files had “lost moral value.”

Mr. Noble said Interpol could not vouch for the content of the messages and other FARC documents. He also explained that the forensic experts who examined the files do not read Spanish, saying this was done purposely to ensure an impartial investigation.

Mr. Noble commended the professionalism of Colombian authorities and stressed that “there was no tampering with or altering of any of the data contained in the user files by any of the Colombian law enforcement authorities.”

Interpol’s findings, after a two-month forensic analysis, could fuel efforts by a small group of Republicans on Capitol Hill to have Venezuela classified as a state sponsor of terrorism. The FARC has long been listed American officials have worried since early in Chavez’s term that the ideological affinity he shared with the FARC had translated into aid. Recently declassified cables, obtained by the nongovernmental National Security Archive in Washington, show how American diplomats in the region believed Chavez was providing secret assistance.