A group of military experts led by two retired general officers will develop a list of alternatives to Puerto Rico's Vieques island as a training range for U.S. naval forces, the Pentagon announced Thursday.

The study group will operate on the assumption that the Navy will abandon its Vieques training range in May 2003, officials said. The group is expected to present its conclusions by spring 2002, the officials said.

The Navy had resisted leaving Vieques, but the accidental killing of a civilian security guard at Vieques in 1999 triggered a public outcry against the Navy there, and last year the Clinton admeferendum to be held in November 2001.

President Bush said in June that the Navy must plan to abandon Vieques by May 2003, and the administration said it intended to ask Congress to remove the requirement for the November referendum.

A Pentagon spokesman, Rear Adm. Craig Quigley, said Thursday the administration has not yet submitted its request to Congress to scrap the referendum.

"We're almost there, but draft legislation has not yet been submitted," Quigley said.

For years the Navy has said there is no single alternative to Vieques because it is the only place where it can simultaneously conduct amphibious landings, naval surface gunfire and air strike operations.

Military officials have called Vieques unique because it has waters deep enough to accommodate aircraft carriers and is able to accommodate aerial war games without interfering with commercial air traffic.

The study announced Thursday will be done under the auspices of the Center for Naval Analyses, a federally funded research center that specializes in Navy and Marine Corps issues. The center named retired Adm. Leighton Smith and retired Marine Corps Gen. Charles Wilhelm to lead the study team.

They will review potential training facilities, sites and methods to find alternatives to Vieques. They also will estimate costs, assess potential environmental concerns and develop a time line for moving the training from Vieques, officials said.