Cuban-American campaigners are calling for a change in US immigration policy, amid growing anger over the deportation on Monday of 15 Cubans.
Relatives of the repatriated Cubans are challenging the deportation
Cubans are allowed stay in the US only if they reach dry land.
But the Coast Guard said the disused bridge the group of 15 had reached on the Florida Keys did not qualify because parts of it had collapsed.
On Tuesday, the US state department called on Cubans not to migrate illegally to Florida.
Spokesman Sean McCormack said Cubans should not risk their lives crossing the Florida Strait, but he stressed that Washington was committed to a policy of safe and legal Cuban immigration.
Florida Senator Mel Martinez, a Republican, called for an overhaul of the so-called "wet-foot, dry-foot" policy, under which the authorities send home those stopped at sea.
"The policy is wrong and it ought to be changed. It's unilaterally violated by Cuba, while we observe the most painful part of it," he said.
Correspondents say the policy has become more stringent in recent years.
Some of the relatives of the Cubans repatriated on Monday are suing the Departments of State and Homeland Security over the incident.
A lawyer for the Democracy Movement, William Sanchez, told the Miami Herald that he wanted a judge to rule whether the section of bridge in question constituted US territory.
Cubans are usually allowed to stay if they touch US soil, bridges, piers or rocks.
But in the case of the 15 Cubans, officials said sections of the abandoned bridge had collapsed between the group's boat and the nearest island.
Some community leaders have warned that the latest deportations could affect backing for the Republican Party among Cuban-Americans, traditionally staunch supporters.
"This will have an effect reducing of the numbers of Cuban-American voters that would blindly follow a Republican candidate," said Pepe Hernandez, the president of the Cuban American National Foundation.
"Cubans are going to realise that both parties come when they need us but tend to forget our pledges when they don't."