U.S. to Return 13 Cubans Picked Up at Sea : Policy: Clinton Administration makes clear it will follow through on new rule to repatriate rafters. Lawyers’ group in Miami seeks to block it.

In what is seen as the first test of a new hard-line Clinton Administration policy denying entry to Cubans attempting to float across the Florida Straits to the United States, 13 men picked up at sea by an American cruise ship will be returned to Havana, a White House spokesman said Friday.

The men, found adrift in two small boats near the Cayman Islands, are the first balseros , or rafters, to face forced repatriation under a Clinton Administration policy announced Tuesday.

“The policy is clear: Migrants intercepted at sea by the U.S. and who are attempting to enter the U.S. will be taken back to Cuba,” said the spokesman.

He added that officials of the U.S. Interest Section in Havana will be at the dock to assist the rafters in applying for asylum and will monitor their treatment by Cuban authorities.

Friday night, however, a U.S. official said that some legal uncertainties remain about whether U.S. law and U.S. policy apply to the Cubans because they now are aboard a Norweigian-owned ship in international waters. The new rules reverse more than three decades of U.S. policy and caused a furor in much of Miami’s Cuban American community. Many of those who denounced the policy switch expressed outrage that the Administration had negotiated secretly with the government of Fidel Castro.

The Administration will allow into the United States the 21,000 Cubans at the U.S. naval base at Guantanamo Bay, Cuba--the last of the rafters who attempted to enter this country last year. But it wanted to send a signal that another chaotic balsero exodus will not be tolerated.

As news of the U.S. government’s intention spread Friday, a group of Cuban American lawyers scrambled to find a legal way to block the repatriation.

Sen. Bob Graham (D-Fla.) said he met with National Security Council advisers Friday and was assured that any political asylum claims made by the Cubans would be heard.

Rep. Ileana Ros-Lehtinen (R-Fla.) said that she attempted to intervene on the Cubans’ behalf. But immigration officials, she said, “believe their policy is clear--that everyone is going to be sent back.”

A U.S. Coast Guard cutter was to rendezvous with the Miami-based Majesty of the Seas near Cuba’s east coast late today or Sunday to take the Cubans aboard. Neither White House nor Coast Guard officials in Miami seemed certain late Friday whether the Coast Guard ship would sail into Havana with the 13 men or whether they would be transferred to a Cuban vessel offshore.

The Majesty of the Seas, heading toward Miami near the end of a weeklong Caribbean cruise, encountered the men late Wednesday about 45 miles south of Little Cayman Island.

According to Jill Oren of the Royal Caribbean Cruise Lines, the 13 men were in distress when taken aboard but were healthy. They were given food, water and medical attention, she said.

The ship is scheduled to dock in Miami on Sunday morning.

The Administration spokesman said that the 13 Cubans were the first to be picked up since the new policy was announced Tuesday and added that the United States has “no evidence that a mass exodus was under way.” The Cubans may have set sail from the Cayman Islands, where several hundred balseros landed during last year’s migration.

Traditionally, however, spring and summer is the sailing season for Cubans and Haitians attempting to enter this country. Through April, the Coast Guard has picked up 376 Cubans at sea, all of whom were taken to Guantanamo. Another 126 Cuban rafters made landfall in Florida this year, and were released to family or sponsors.

Clary, a special correspondent, reported from Miami and Broder, a Times staff writer, reported from Washington.