Fifteen Cubans who fled their homeland and landed on an abandoned bridge piling in the Florida Keys were returned to their homeland Monday after U.S. officials concluded that the structure did not constitute dry land.

Under the U.S. government's "wet-foot, dry-foot" policy, Cubans who reach dry land in the United States are usually allowed to remain in the country, while those caught at sea are sent back.

The Cubans -- including a 2-year-old boy and a 13-year-old boy -- were sent back around midday, said a Coast Guard spokesman, Officer Dana Warr. They were rescued last week and were held aboard a Coast Guard cutter while they awaited a final decision on their status.

The case presented U.S. officials with an intriguing legal question.

The Cubans thought they were safe Wednesday when they reached the Old Seven Mile Bridge. But the historic bridge, which runs side by side with a newer bridge, is missing several chunks, and the Cubans had the misfortune of reaching pilings from a section that no longer touches land.

The federal government said that means the group never actually reached U.S. territory, and could be sent home.

An attorney for relatives of the Cubans filed an emergency request Monday asking the government to review the question of whether the bridge constitutes dry land. But the attorney apparently was unable to keep the Cubans from being sent back.

The Cubans had left Matanzas Province in Cuba late on the night of Jan. 2 aboard a small, homemade boat. They were rescued by the Coast Guard from the base of the bridge just south of Marathon Key.

"The particular structure that they were found upon is not connected to land. The `bridge' is kind of a misnomer," said Coast Guard Lt. Commander Chris O'Neil, spokesman for the department's Southeast region.

O'Neil said officials in Washington determined the Cubans should be considered "feet wet," because they were not able to walk to land from where they landed.

Before the Cubans were returned, at least a dozen Cuban-Americans protested their situation Monday outside the Coast Guard headquarters in Miami Beach.

"They are trying to go as far as they can ... to take away the immigrants' rights," said Ramon Saul Sanchez, head of the Democracy Movement, a Cuban-American group.

Veteran immigration attorney Ira Kurzban, who was not involved in the case, called the Coast Guard decision ridiculous.

"The wet-foot, dry-foot policy has no foundation in law," he said. Kurzban said the policy is inconsistent with U.S. and international law, noting that the federal government's jurisdiction extends beyond dry land to waters as far out as 100 miles.

"International law says that refugees should be granted a hearing before they are forcibly returned," he said.