An FBI agent testified in federal court Thursday that the man accused of heading an alleged Cuban spy ring, hours after his arrest, defended Havana's shootdown of four Brothers to the Rescue airmen as a ``lamentable act,'' but blamed Brothers founder José Basulto for the deaths.

The conversation -- not recorded, and some parts recalled for the first time Thursday, five months later -- is the focus of a tug-of-war between federal prosecutors and the defense over whether it will be evidence at the September trial of Manuel Viramontes.

It is the only clue in public court records that the government is trying to link alleged spymaster Viramontes and his 10-member espionage ring to the shootdown. Another spy suspect, Rene Gonzalez, 42, was once a Brothers pilot.

Viramontes' attorney, Paul McKenna, argued that the FBI agent -- Cuba-born, Puerto Rico-based Oscar Montoto -- had baited Viramontes in an effort to link the Sept. 24, 1996 shootdown to the spy case.

Viramontes, 32, who is listed in court documents as John Doe No. 1, because federal officials believe he is using a fake identity, was arrested with nine other people Sept. 12, and accused of spying on Cuban exile groups and U.S. military bases in South Florida.

All 10 were captured in an early morning sweep that rousted the suspects from their beds. Five have agreed to plead guilty to lesser charges in exchange for their cooperation against the other five, who are characterized as more significant figures.

Montoto alternately said in court that he has both major and peripheral roles in a ``massive,'' ongoing FBI investigation into the shootdown.

Previously based in Miami, where he worked on counter-intelligence cases, Montoto said he was involved in the shootdown investigation from the start when, on the evening of the tragedy, he interviewed Basulto, pilot of the only Brothers plane to survive.

Then, two and a half years later, he said, he came to help on the spy arrests and found himself in the back seat of an FBI car that was taking Viramontes to jail, five hours after his arrest. Montoto said that, without prodding, which would have been wrong because Viramontes wanted a lawyer, the accused spymaster said the shootdown was ``a lamentable act.''

According to Montoto's account, Viramontes also inexplicably blurted out that he was ``not a communist,'' and that ``he was not here to work against Special Agent Montoto's government.''

``His main objective,'' according to Montoto's report that day, now quoted in court records, ``was to work against groups that continuously threaten the Cuban people -- that place bombs and set out on excursions to shoot at the Cuban coast.''

These statements could also be key to Assistant U.S. Attorney Carolyn Heck Miller's case because she claims that Viramontes is lying when he says he is a Texas-born U.S. citizen. Before his arrest, in an North Miami Beach apartment, he was working as a graphic artist.

Montoto also reported that Viramontes allegedly said the the Cuban government repeatedly complained to the United States about Basulto's violations of Cuban airspace, without any results.

``He accounted [sic] that it was a lamentable act but it solved the problem,'' he testified.

``He placed the blame on José Basulto. He said, `If anyone's to blame, it's José Basulto.' ''

Cuban MiGs rocketed two small, slow-moving Brothers aircraft over international waters. U.S. officials call the crime ``cold-blooded murder'' but have not indicted anyone. Family members of three of the dead airmen, meanwhile, sued the Cuban government in civil court and won a $187 million judgment.

Considered in one light, the conversation could be seen as an admission of first-hand knowledge of the shootdown. Considered in another, it could be a classic confrontation between two South Floridians with different takes on whether Basulto's pre-shootdown actions were provocations.

Viramontes sat silently throughout the proceedings, in a khaki-colored jail uniform, listening through headphones to a Spanish-language interpreter and sometimes shaking his head in disagreement. Several family members of the men killed in the shootdown also watched the proceedings.

Miller argued in a government brief that Viramontes made the remarks spontaneously and they should be admissible to the case.

U.S. Magistrate Robert Dubé gave both sides until March 11 to file addition briefs.

The spy trial itself will be heard by U.S. District Judge Joan Lenard, who is now considering which classified U.S. intelligence material may be available to defense lawyers.

All 10 spy suspects, meantime, are in jail.