(Adds Trump tweet, efforts to roll back Obama legacy)
WASHINGTON, June 16 (Reuters) - U.S. President Donald Trump on Friday will announce plans to tighten restrictions on Americans traveling to Cuba and clamp down on U.S. business dealings with the islands military, rolling back parts of former President Barack Obamas historic opening to Havana.
Laying out his new Cuba policy in a speech in Miami, Trump will issue a presidential directive to reverse some of the loosened regulations that Obama introduced after a 2014 breakthrough between the two Cold War foes, senior White House officials said.
Trump, taking a tougher approach against Havana after promising to do so during the presidential campaign, will outline stricter enforcement of a longtime ban on Americans going to Cuba as tourists and seek to prevent U.S. dollars from being used to fund what the new U.S. administration sees as a repressive military-dominated government.
But facing pressure from U.S. businesses and fellow Republicans to avoid turning back the clock completely in relations with communist-ruled Cuba, the president will leave intact many of Obamas steps toward normalization.
Trump tweeted on Friday that his new approach would "empower the Cuban people and hold the regime accountable."
The new policy will ban most U.S. business transactions with the Armed Forces Business Enterprises Group, a Cuban conglomerate involved in all sectors of the economy, but make some exceptions, including for air and sea travel, according to U.S. officials and a draft presidential directive seen by Reuters. This will essentially shield U.S. airlines and cruise lines serving the island.
However, Trump will stop short of closing embassies or breaking diplomatic relations restored in 2015 after more than five decades of hostilities. He will not cut off recently resumed direct U.S.-Cuba commercial flights, though his more restrictive policy seems certain to dampen new economic ties.
(For a graphics package on Cuban tourism, see: http://tmsnrt.rs/2rBfMTI)
The administration, according to one White House official, has no intention of disrupting existing business ventures such as one struck under Obama by Starwood Hotels Inc, which is owned by Marriott International Inc, to manage a Havana hotel.
Nor does Trump plan to reinstate limits that Obama lifted on the amount of the islands coveted rum and cigars that Americans can bring home for personal use.
While the changes are far-reaching, they appear to be less sweeping than many U.S. pro-engagement advocates had feared.
Still, it will be the latest attempt by Trump to overturn parts of Obama's presidential legacy. He has already pulled the United States out of a major international climate treaty and is trying to scrap his predecessor's landmark healthcare program.
REPAIR 'BAD DEAL'
Trump will justify his partial reversal of Obamas Cuba measures to a large extent on human rights grounds. His aides contend that Obamas efforts amounted to "appeasement" and have done nothing to advance political freedoms in Cuba, while benefiting the Cuban government financially.
Saying the aim was to repair what Trump has called Obama's bad deal, U.S. officials said the new administration would leave the door open to improved relations if Cuba allows free elections and releases political prisoners.
International human rights groups say, however, that isolating the island could worsen the situation by empowering Cuban hard-liners. The Cuban government has made clear it will not be pressured into reforms in exchange for engagement.
The Cuban government had no immediate comment, but ordinary Cubans said they were crestfallen to be returning to an era of frostier relations with the United States with potential economic fallout for them.
"It's going to really hurt me because the majority of my clients are from the United States," said Enrique Montoto, 61, who rents rooms on U.S. online home-rental marketplace Airbnb, which expanded into Cuba in 2015.
Trumps critics have also questioned why his administration is now singling out Cuba for its human rights record but downplaying the issue in other parts of the world.
Trump will announce his new approach at the Manuel Artime Theater in Miamis Little Havana, the heart of the largest Cuban-American community in the United States, whose support aides believe helped him win Florida in the election.
Republican Senator Marco Rubio, a key player in forging the new policy, was expected to attend along with other Cuban-American lawmakers.
Under Trumps order, the Treasury and Commerce Departments will be given 30 days to begin writing new regulations and they will not take effect until they are complete. No deadline has been set, the officials said.
Under the revised travel policy, U.S. officials said there will be tighter enforcement to make sure Americans legally fit the 12 categories they are traveling under, which could spook many visitors, wary of receiving a hefty fine.
While tourism to Cuba is banned by U.S. law, the Obama administration allowed people to travel to Cuba as part of people to people educational trips, a popular classification that a White House official said was ripe for abuse by those looking for beach vacations.
Trumps new policy will eliminate such self-certified visits by individuals but allow them as group tours. It retains some individual travel under categories like religious, artistic and journalistic activities, officials said.
Some aides argued that Trump, a former real estate magnate who won the presidency vowing to unleash U.S. business, would have a hard time defending any moves that close off the Cuban market. But other advisers have contended that it is important to make good on a campaign promise to Cuban-Americans.
(Additional reporting by Lesley Wroughton and Patricia Zengerle in Washington, Sarah Marsh and Marc Frank in Havana; Editing by Michael Perry and Jeffrey Benkoe)