A statement from the U.S. Coast Guard confirmed that Cuba would take the lead role in handling the crisis in the Florida Straits separating the two countries.
"The Coast Guard is aware of a report of a suspected Cuban vessel hijacking. We stand ready to assist the Cuban government with fulfilling their obligations under international law," the statement said.
"What we won't do in any case is to use measures of force that put in danger the lives of the people aboard this boat," Cuba said in its first statement on the ferry hijacking.
The ocean drama was the result of the second hijacking from Cuba in as many days. A passenger plane was highjacked to Key West, Florida, on Tuesday by a man who allegedly threatened to blow up the aircraft with two grenades that later turned out to be fake.
The Soviet-made AN-24 plane had taken off from Jose Marti International Airport and landed in Florida less than an hour later. After the plane crossed into American airspace, it was escorted by two F15-Eagles from Homestead Air Force Base in Florida.
The hijacker was carrying a small boy in his arms when he came off the plane, Key West police spokesman Steve Torrence said. He was taken into FBI custody.
The latest crisis began early Wednesday when a group of people armed with three pistols and at least one knife hijacked the ferry overnight, Havana said in a statement read on state television.
The ferry is one of several providing regular service between Havana and the small communities of Casablanca and Regla on the other side of Havana Bay.
In Miami, the U.S. Federal Bureau of Investigation said that the ferry on Wednesday morning was drifting in international waters about 60 miles off Key West.
FBI spokeswoman Judy Orihuela said Cuban officials told her agency that there were 15 to 20 people aboard the 45-foot craft. There was no immediate explanation for the differing figures.
Orihuela said the FBI was sending hostage negotiators to the scene by helicopter, where they were to rendezvous with a U.S. Coast Guard cutter.
There were no other details about what was transpiring between the hijackers and the Cuban and U.S. authorities out on the open sea.
The Cuban statement said two Cuban Coast Guard boats had followed the ferry out to the high seas, where they will remain during the crisis to provide assistance in an emergency or to escort the ferry back to Cuba should the hijackers decide to turn the boat around.
The ferry hijacking came less than 24 hours after the Cubana Airlines passenger plane was hijacked to Key West. Another Cuban passenger plane was hijacked to Key West less than two weeks before that.