Three badly hurt Cuban migrants were plucked from the sea off Miami today and authorities launched a search for nearly a dozen others who may have been on a small boat that sank off the Florida coast, police said.

Fishermen rescued a 23-year-old woman and a 33-year-old man clinging to an inner tube off Key Biscayne just east of the Florida mainland early this morning, police said.

The pair, in critical condition from exposure, told police that they left Matanzas, Cuba, on Sunday in a 17-foot aluminum boat with 12 other people and that the boat sank at least two days ago.

"They said either Monday or Tuesday they encountered rough seas and real bad weather, and the boat sank," Metro-Dade Police Detective Ed Munn said. "They managed to grab this inner tube on the boat."

A short time after the two were found off Key Biscayne, a 5-year-old boy was discovered clinging to an inner tube off Haulover Inlet near Miami, miles to the north. He was believed to be from the same boat.

The body of an elderly woman also was found at sea several miles to the north, off Fort Lauderdale. It was not known if she was from the same boat, the U.S. Coast Guard said.

The Coast Guard and local police agencies launched a massive search for the missing people. Coast Guard ships and aircraft scoured Florida waters while police searched beaches and coastal areas.

Each year, hundreds of Cubans leave their Communist-ruled homeland in small boats and makeshift rafts in an attempt to cross the Florida Straits to U.S. shores. The Caribbean island and Florida are separated by just 90 miles at their closest point.

So far this year, 1,261 Cubans have been interdicted at sea by the U.S. Coast Guard, compared with 1,047 for all of last year. Under the U.S. "wet feet/dry feet" policy, Cubans who reach the United States are generally allowed to stay while those intercepted at sea are usually sent home.

The 5-year-old boy was found by a boater and was taken to a Fort Lauderdale area hospital, Coast Guard spokesman Scott Carr said.

"He was weak, in and out of consciousness. If the boat went down Monday, he's been in the water for days," Carr said. "He told Coast Guard officers that both his parents were deceased. We believe the boy was part of the group."

Although it was uncertain how far offshore the boat sank, the woman told authorities she believed that she had seen a city skyline when the boat capsized and that the pair had been in the water for at least two days, Munn said.

"They had exposure, sunburn. They were somewhat battered. It was obvious they had been in the water for a long time," Munn said.

The two were reported in critical but stable condition at Jackson Memorial Hospital in Miami.