The leaders of three Puerto Rican political parties are demanding the U.S. Senate authorize a 1991 plebiscite on whether the island should be independent or remain tied to the United States.

Gov. Rafael Hernandez Colon, who favors the island's present U.S. Commonwealth status and who leads the Popular Democratic Party, was among the leaders who sent a letter to a Senate committee."It would be undemocratic and contradictory that Congress should not respond promptly and decisively to the request of 3.6 million citizens from Puerto Rico to be consulted as to the choice of their ultimate political status," the letter read.