By REUTERS

MIAMI -- Three Cubans and the body of a fourth were plucked from the sea on Thursday, and the authorities began searching for 10 others who may have perished when their small boat sank off the Florida coast, officials said.

The Cubans who were rescued -- a 5-year-old boy, a 23-year-old woman and a 33-year-old man -- had apparently survived two days in the Atlantic Ocean clinging to inner tubes, the police and the United States Coast Guard said.

The man and the woman, who were in critical but stable condition from exposure, told the authorities that they had left Matanzas on Sunday with 12 other people. Their 17-foot aluminum boat sank in rough weather on Tuesday, they said.

"They said after the initial accident, seven people drowned," said a Coast Guard spokesman, Scott Carr. "That left seven survivors. So we're really searching for three possible survivors."

Each year hundreds of Cubans leave their homeland in small boats and makeshift rafts in an effort to cross the Florida Straits and reach the United States.

Fishermen found the surviving man and woman around dawn on Thursday off Key Biscayne, an island connected to Miami by causeways and bridges.

A short time later, boaters found the boy clinging to an inner tube off Fort Lauderdale, about 25 miles to the north. The authorities also recovered the body of an elderly woman, Carr said.

"We thought someone had tied a dummy to a raft," Sam Zianzio, who spotted the boy, told a local radio station. "I dove into the water after the kid, and the kid was just shaking."

The boy was in stable condition at a hospital near Fort Lauderdale.

Carr said the survivors had told the authorities that after the accident, they split into two groups: the man and the woman on one inner tube, and the five others, including the boy and the elderly woman, on another.

A Coast Guard cutter, three helicopters and other vessels were scouring a section of the Atlantic from Islamorada in the Florida Keys to Boca Raton on the state's east coast and about 35 miles out to sea. Local police officers searched beaches and coastal areas for survivors and bodies.

The presumed deaths dimmed Thanksgiving celebrations in Miami, the heartland of the Cuban diaspora. Members of the Cuban exile group Brothers to the Rescue joined the search, flying small planes over coastal waters in search of survivors.

"It's very sad," said Ninoska Perez, spokeswoman for the Cuban American National Foundation, an exile group. "It's sadder because it's an ongoing tragedy. The Cuban people have been going through this for 40 years."

Although it was uncertain how far off shore the boat sank, the woman told the authorities she thought she had seen a city skyline when the vessel capsized, the police said.

"They had exposure, sunburn," said Detective Ed Munn of the Miami-Dade Police Department. "They were somewhat battered. It was obvious they had been in the water for a long time."

So far this year, 1,261 Cubans have been stopped at sea by the Coast Guard, compared with 1,047 for all of last year. Crossings are usually attempted in the summer, when placid seas and light winds make the trip easier, and taper off toward winter when conditions are less favorable.

Under the United States' "wet feet/dry feet" policy, Cubans who reach the mainland are generally allowed to stay, while those intercepted at sea are usually sent home.

The immigration authorities were unavailable to comment on the future status of the rescued Cubans.