By DAVID JOHNSTON

          WASHINGTON, April 27 -- Prodded by the Pentagon, federal
          authorities are preparing a sea-and-land law enforcement
          operation next week on Vieques, a small island off Puerto Rico, to clear
          demonstrators from a Navy bombing range there, government officials
          said today.

          Preparations to move a large number of federal special weapons and
          tactics teams to Vieques are under way less than a week after armed
          immigration officers stormed a house in which the Cuban boy Elián
          González was staying with his great-uncle in Miami.

          As the furor over the Miami operation continues, Attorney General Janet
          Reno has been planning the much larger and potentially risky operation in
          Vieques. She has met with the director of the Federal Bureau of
          Investigation, Louis J. Freeh, whose agents would play a central role in
          the assault, and with Defense Secretary William S. Cohen, the officials
          said.

          The Vieques protesters have been demonstrating against an agreement
          reached on Jan. 31 by President Clinton and Gov. Pedro J. Rosello of
          Puerto Rico. The deal allowed the Navy to conduct limited exercises on
          Vieques in exchange for an American promise to abide by a referendum
          in Puerto Rico on whether to close the range.

          The officials said that most days 50 to 75 protesters are camped on the
          island in the path of aircraft on bombing runs. Their ranks are expected to
          swell as knowledge of a pending operation spreads. Protesters are
          expected to arrive by boat and congregate at entry gates to the base.

          Today, a Pentagon spokesman, Rear Adm. Craig Quigley, said that the
          Pentagon had been consulting with other government organizations, but
          would not discuss the status of the law enforcement operation.

          "We've been in consultation with the Puerto Rican government, with the
          Department of Justice, to work out a way to clear the range of the
          trespassers," Admiral Quigley said. "That process continues, and I am
          just not going to go into any further detail on that process at all."

          Several civilian federal agencies are involved in the law enforcement
          operation, the officials said. Among them are the Treasury Department
          and the Transportation Department, which has jurisdiction over the Coast
          Guard, which would help block the flotillas of demonstrators expected to
          arrive by sea from Puerto Rico.

          The officials said that federal authorities are prepared to clear the
          bombing range, but have expressed serious reservations about the
          operation, which is scheduled for next week if the White House approves
          it.

          They said that Pentagon officials have been insistent that the Navy
          needed the bombing range for training exercises, even though Justice
          Department officials have said that another military-style assault would
          provoke another avalanche of criticism of the Clinton administration.

          The officials said they feared that neither the F.B.I. nor the federal
          marshals were adequately prepared for such a large-scale enforcement
          action so far from the mainland.

          The operation would take place over a large area in which there would
          be virtually no chance for a surprise raid, on beaches and open terrain
          including some areas where live munitions are thought to lie.

          Moreover, the officials said, they feared the law enforcement operation
          would provoke demonstrations in other parts of Puerto Rico, and that
          local authorities were unprepared for large-scale disruptions.

          Under the tactical plan, the officials said, marines would arrive aboard
          ships to provide perimeter security, but only after the operation, and the
          Puerto Rican police would be responsible for crowd control.

          When the arrangement between the White House and Puerto Rico was
          announced, Mr. Rossello said he would help federal efforts to stop
          trespassing at the bombing range, but little action has been taken against
          the protesters.

          Exercises on Vieques, where the Navy maintains a bombing range that it
          considers essential to the training of its Atlantic fleet, were suspended last
          spring after a wayward bomb killed a civilian security guard, an accident
          that intensified longtime protests against the military presence. The
          Pentagon has been putting pressure on the Justice Department to clear
          the bombing range of protesters. Earlier this year, an aircraft carrier battle
          group had to conduct some training exercises in different places, including
          using a bombing range in Scotland.

          The next carrier group, led by the George Washington, is headed to sea
          in coming months and the Navy is eager to use the range, which officials
          say offers the ideal location for coordinating air-ground-and-sea training
          exercises.