The U.S. and Cuba share no extradition agreement and the island nation is also not a signatory of the Hague Convention on the Civil Aspects of International Child Abduction, an international treaty for governmental cooperation on such cases.
Cuba has harbored U.S. fugitives in the past, though most of those cases date back to the 1960s and 70s, when the island became a refuge for members of the Black Panthers and other militant groups. More recently, dozens of Cuban Medicare fraud fugitives in the U.S. have tried to escape prosecution by returning to the island.
But Cuba has also cooperated with U.S. authorities in returning several criminal fugitives in recent years, including Leonard B. Auerbach in 2008. Auerbach was wanted in California on federal charges of sexually abusing a Costa Rican girl and possessing child pornography. He was deported.
In 2011, U.S. marshals flew to Cuba and took custody of two American suspects wanted in a New Jersey murder.
Hakken lost custody of his sons last year after a drug possession arrest in Louisiana and later tried to take the children from a foster home at gunpoint, authorities said. A warrant has been issued for his arrest on two counts of kidnapping; interference with child custody; child neglect; false imprisonment and other charges.
"My team and I working very hard to ensure safety for two Amcit kids," Conrad Tribble, the No. 2 U.S. diplomat on the island, said via Twitter later Tuesday, using a shorthand for "American citizens."
According to the Hillsborough County Sheriff's Office, Hakken entered his mother-in-law's Florida house last Wednesday, tied her up and fled with his sons. Federal, state and local authorities searched by air and sea for a boat Hakken had recently bought. The truck Hakken, his wife and the boys had been traveling in was found Thursday, abandoned in Madeira Beach, Florida.