Image copyright Getty Images Image caption Some cruise companies will be among the first defendants.

Javier Garcia Bengochea, a medical doctor who migrated to the United States 59 years ago, says he is the true and legitimate owner of the port of Santiago de Cuba.

And Michael Behn, an American living in the United Kingdom, states that he is the unquestionable owner of Havana's docks.

Both of them - as well as other Cuban-Americans and US citizens claiming to have lost their assets on Cuba after Fidel Castro's Revolution - will be able to bring before federal courts the foreign companies that operate on the properties confiscated from them in the island.

The claims will be possible because US President Donald Trump decided last April to activate Title III of the Helms-Burton Act, a bill passed by Bill Clinton in 1996 to sanction the Havana government for shooting down two US planes.

This is the first time, since the law was approved, that the White House authorises the implementation of an article that has already caused conflict and put in jeopardy the United States' relations with the European Union, one of Cuba's main commercial partners.

This time, though, Trump, as part of his measures against the island for allegedly providing military aid to President Maduro in Venezuela - an accusation that Havana denies - took a step that the leaders before him hesitated to take.

Image copyright AFP Image caption Former President Bill Clinton passed the law in 1996, but since then, successive administrations had signed a moratorium on Title III every six months.

Cuba's government vehemently rejected the activation of Title III and deemed it an "attack on international law" and its sovereignty.

Carnival Cruise, on the other hand, the first company to be sued, said in a statement to BBC Mundo that they are "monitoring the situation" and they do not foresee any changes in their schedules.

Meanwhile, in Miami and its surroundings, the families that have been waiting for more than half a century for this moment, are already rubbing their hands.

According to data from the US Justice Department, Cuban-Americans who say that their properties were seized during the Cuban Revolution have filed more than 200,000 claims.

The US government has "certified" around 6,000 cases of American citizen or companies who also say that their properties in the island were taken away from them after 1959.

Image copyright AFP Image caption Dozens of Cubans in the United States are preparing to sue foreign companies operating in Cuba.

However, Nick Gutierrez, the president of the "National Association of Cuban Landowners", a non-profit company made up of wealthy proprietors from the island, says that not all those who were "affected" by the seizures are eligible to file a lawsuit.

According to the Act, those who may be eligible to seek to regain their properties have to meet the following criteria:

have properties worth more than $50,000 USD when seized (equivalent to more than $427,000 today)

the properties in dispute have to be currently in commercial use

there must be no Cubans or diplomats resident there

plaintiffs must pay a fee of $6,700

"These lawsuits can take years and cost a lot of money, but we hope that they can lead to agreements between those involved and that the owners obtain a compensation for the use of their property," Gutierrez says.

Image copyright AFP Image caption A Cuban living in Florida claims to be the owner of Cuba's main airport and its airline

Despite the restrictions, the attorney says that several Cuban-Americans have already expressed interest in joining the lawsuits filed on Thursday by Garcia Bengochea and Behn.

Among the families interested in suing, Gutierrez mentions the Sanchez Hill family, whose descendants are planning to sue the Melia and Blau groups for using buildings seized from them in the western province of Holguin.

Also planning to file a lawsuit is Jose Ramon Lopez, who says he is the owner of the Jose Martin International Airport, in Havana, and of the Cubana de Aviacion airline.

Another plaintiff is Viriato Carrillo, who says his family owned eight sugar fields, and a food factory, a plant that produces matches, and a distillery of rum, where the French firm Pernod Ricard currently produces the Havana Club rum.

"We're preparing to file something big, but we won't be giving any details, because 'a foretold war kills no soldier' and we don't' want to give information that could help Cuba prepare in advance," he told BBC Mundo.

Image copyright Getty Images Image caption The Carrillo family say they are the owners of the factory where Havana Club rum is produced

The Cuban government has shown "willingness" along the years to negotiate a possible compensation to the American citizens affected by the seizing of properties and working groups of both nations have met in several instances.

The caveat?

Cuba has put as a condition to the US a payment for the damages caused by the economic "blockade" it has imposed on the island during the last 60 years, which Cuban authorities estimate has cost the island around $933,678m, according to the latest official report issued in 2018.

Since 1959, Washington has frozen Cuban funds that have gone through any American bank and that, according to a 2000 US law, could be used to pay for compensations to Americans who lost their properties in Cuba.

But the failure to reach an agreement about how to distribute the funds has remained a hurdle since then.

Despite the excitement that caused Trump's announcement among the most radical Cuban exiles in South Florida, experts approached by BBC Mundo, say that it is, in reality, "a risky and uncertain proposition".

Image copyright Getty Images Image caption Between 1960 and 1968 Fidel Castro eliminated all forms of private property in Cuba

"The Helms-Burton and, in particular Title III, is a law that is very poorly written, very vague and wasn't properly thought through since it was drafted as a summary and there are many questions regarding the actual impact of Title III," says Jose Gabilondo, professor of law and finance at Florida International University.

He considers that there are many doubts about the legal basis of the law and about the jurisdiction that US federal tribunals could have over the defendants which, for the most part, are foreign companies.

Even if it happens, says Prof Gabilondo, it is unlikely that the companies involved have any assets in the United States that could be taken into account for the trial.

There is also the fact, he adds, that many countries such as Mexico, Canada or the European Union - all of them with assets in the island - have taken measures to protect their investors. In other words, the possible impact of the Act remains to be seen.

On 2 May, EU foreign policy chief Federica Mogherini announced that the bloc could present a case against the US before the World Trade Organization or use a "blockade statute" so that companies can recover the potential damages of US plaintiffs in European courts.

However, Prof Gabilondo considers that the possibility of new demands - which he thinks will not exceed 100 - could have a negative effect on the island.

"Any company (already) in Cuba or planning to invest there, could take the Act into account and that is why I think the impact (of the Helms Burton) will translate into scaring investors and limiting the amount of foreign capital coming into the island," he said.

The Cuban government, on the other hand, has assured that foreign companies will be able to "enjoy all the guarantees for investment".

"They are being backed by Cuban laws, international law and the laws of their own countries," says Cuban Foreign Minister Bruno Rodriguez.

Carnival Cruise, Pernod Ricard and Meliá, at the moment, have announced that they will continue with their usual operations on the island.