Cuban and U.S. officials were in Mexico City for private talks on renewing a 1984 immigration agreement suspended by Havana last year. In Washington, State Department sources said the talks are being held but gave no details. The U.S. delegation is headed by Michael Kozak, a State Department legal adviser who negotiated the original agreement. The Cuban negotiators are headed by Deputy Foreign Minister Ricardo Alarcon. The immigration treaty was suspended by Cuban President Fidel Castro in protest over the establishment of Radio Marti, which began anti-Communist transmissions directed at the island nation from the Florida Keys in May, 1985.