An attache to the Cuban mission at the United Nations was shot to death yesterday while driving his car in Queens. An anonymous caller claimed that an anti-Castro terrorist group was responsible.

Police said Felix Garcia-Rodriguez was driving in a heavily populated commercial area about 6:30 p.m. when he was shot in the neck. His station wagon, which bore diplomatic license plates, swerved onto a sidewalk and crashed into another car. No other injuries were reported.

Police said three .45-cal. shell casings were found at the scene, leading them to believe the victim had been shot by persons in a passing vehicle. However, a man riding a moped directly behind Rodriguez' car told police he did not see any vehicles pass the attache's auto.

An anonymous male caller told the Associated Press that Omega 7, a terriorist group opposed to Cuban President Fidel Castro, had "executed a member of the Cuban delegation to the United Nations."

He warned that Raul Roa, the Cuban ambasador to the United Nations, would "be next."

In Washington, Secretary of State Edmund S. Muskie expressed "deep regret" over the slaying, adding that "federal agencies" will enter the investigation.

"This is a nation of laws. We condemn terrorism in all its forms and are committed to its eradication," Muskie said.

Omega 7 has claimed responsibility for several bombings in New York City, including one Dec. 7 at Cuba's U.N. mission in mid-Manhattan. Two policemen were hurt in that incident.