The Trump administration is opening the door for lawsuits against foreign firms operating on properties Cuba seized from Americans after the 1959 revolution.
The White House's national security adviser, John Bolton, says the Trump administration won't renew a bar on litigation in place for two decades.
The decision is a blow to Havana's efforts to draw foreign investment to the island.
The decision gives Americans the right to sue companies that operate out of hotels, tobacco factories, distilleries and other properties Cuba nationalized after Fidel Castro took power. It allows lawsuits by Cubans who became U.S. citizens years after their properties were taken.
"My father lost everything in 30 seconds. He lost a huge business that he established. "Says Juan Montes, a retired U.S. Army Colonel and Cuban exile. "If there is a chance to return the property to myself and my daughters and granddaughters, definitely, I will fight for that."
Bolton also announced The U.S. will be restricting some travel to Cuba that's not related to family visits, that some non family trips to Cuba are portrayed as tourism, but they aren't really for sightseeing. He says the new measures will help steer U.S. dollars away from the Cuban government, its military or its security services.
The announcement drew sharp criticism from Spain, the EU and Canada.
The Spanish government says Washington's move damages relations between Europe and the United States and will lead to lawsuits and counterclaims.
Spanish companies are among Cuba's main foreign investors.