The administration Wednesday announced tight new restrictions on American travel and commercial exchanges with Cuba, implementing a policy announced by President Trump five months ago to reverse Obama administration normalization with the Communist-ruled island.

Under the new rules, most individual visits to Cuba will no longer be allowed, and U.S. citizens will again have to travel as part of a licensed group, accompanied by a group representative. Americans will also be barred from staying at a long list of hotels, and patronizing restaurants, stores and other enterprises that the State Department has determined are owned by or benefit members of the Cuban government, specifically its security services.

The new rules “are intended to steer economic activities away from the Cuban military, intelligence and security services . . . and encourage the government to move toward greater economic freedom” for the Cuban people, according to a senior administration official, one of several authorized by the White House to brief reporters on the changes on condition of anonymity.

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Commercial relations with Cuba are to be similarly restricted to prevent any exchanges with the 180 entities on the State Department list.

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Administration officials said that the new regulations, which go into effect Thursday, would not effect travel arrangements already made or contracts already signed, which are to be grandfathered under existing law.

President Barack Obama restored diplomatic ties with Havana in 2015 and issued regulatory changes that allowed increased commercial relations and expanded travel to Cuba.

Trump, who said during his campaign that he would “terminate” the Obama normalization if Cuba would not cut a “better deal” with the United States, announced during a June speech in Miami’s Little Havana that changes would be made.

“Our policy will seek a much better deal for the Cuban people and for the United States of America,” Trump said in the speech. “We do not want U.S. dollars to prop up a military monopoly that exploits and abuses the citizens of Cuba.”

Much as Obama used his regulatory authority to loosen restrictions within an ongoing U.S. economic embargo on Cuba, Trump has now changed those regulations to retighten them.

Although the amount of trade under the Obama changes has not expanded as much as anticipated, a number of U.S. business and agricultural entities have sought contracts in Cuba. American travel to the island has increased exponentially.

Collin Laverty, who organizes educational travel to the island, said that “at a time that President Trump is meeting with Communist leaders in China and Vietnam, these regulations show the absolute hypocrisy and political pandering of the Trump administration in Cuba. They serve to placate a fading minority in South Florida, harming American and Cuban workers and families.”