WASHINGTON (Reuters) - U.S. companies are looking for ways to persuade President-elect Donald Trump to soften his threats to cancel the Obama administration’s opening to Cuba, a reversal they fear could cost them hundreds of millions of dollars.

U.S. President-elect Donald Trump yells to members of the media from the steps of the main clubhouse at Trump National Golf Club in Bedminster, New Jersey, U.S., November 19, 2016. REUTERS/Mike Segar

During his campaign, Trump said he thought restoring diplomatic ties with Cuba was fine, but that Democratic President Barack Obama should have pushed harder for concessions from Havana before easing restrictions on travel and trade.

On Monday, three days after the death of revolutionary leader Fidel Castro, the Republican president-elect said in a Twitter post that he would end what he referred to as Obama’s “deal” if Cuba did not do more for its people.

But he did not promise to reverse the changes, and advocates for closer ties said they hoped the businessman-turned-politician would stay true to his roots and foster economic ties.

“He has said things that are frankly hopeful to folks on both sides of the debate,” U.S. Representative Mark Sanford, one of several Republican lawmakers who back increased engagement, told Reuters.

Trade associations for companies with business interests in Cuba hope to persuade Trump to continue Obama’s opening, and have been discussing a joint effort to press the Republican’s administration, a person with knowledge of the talks said.

Trump won the White House on promises to create jobs. Advocates for increased engagement argue that promoting U.S. trade with Cuba would create opportunities, and jobs, in industries from telecommunications to agriculture, and particularly in tourism.

SMALLER PIECE OF CAKE

Several U.S. airlines are already flying to Cuba, Starwood Hotels & Resorts signed a contract to manage a Cuban hotel and Carnival Corp has begun cruises to the island.

While business in Cuba has yet to generate much revenue for U.S. companies, reversing Obama’s policies could leave Americans out of a potential market or mean their investments so far have been wasted.

“If the U.S. continues to limit trade (with Cuba), and the European Union, China and Russia continue to expand trade, there will be a smaller piece of cake left for U.S. companies,” said Jose Maria Vinales Camallonga, director of International Operations at Lupicinio, a Spanish law firm that represents large corporations in their Cuba dealings.

As Trump issued his tweet on Monday, American Airlines Flight 17, the first commercial flight in more than half a century between the United States and Havana took off for the Cuban capital, part of a wider push by U.S. carriers to boost flights there.

If flights stopped or demand slipped because Trump imposed new travel restrictions, U.S. airlines could lose hundreds of millions of dollars in potential revenue in the years to come, said John Kavulich, president of the U.S.-Cuba Trade and Economic Council.

The Department of Transportation has authorized 1.2 million seats for trips to Cuba by commercial U.S. carriers per year, below the 3.4 million airlines requested, but representing significant revenue, he said.

Cuba also represents a potential market for U.S. products such as chickens, wheat and rice, though U.S. farm exports to the island have actually fallen since Obama and Cuban President Raul Castro moved to normalize relations in December 2014.

Still, lawmakers from several states with big agricultural sectors like Arkansas and Texas back closer ties.

If Trump reversed Obama’s Cuba policies “he would have to take on one of his main constituencies, which is the business community,” said Julia Sagebien, an expert on Cuban business at Dalhousie University in Nova Scotia.

In a bid to cement Obama’s Cuba policy before Trump takes over on Jan. 20, the administration has been encouraging U.S. companies to forge further business deals.

More than half a dozen announcements, in areas from travel to manufacturing to telecommunications, had been expected in the next two months, a person familiar with the matter said. But Fidel Castro’s death and uncertainty about Trump’s plans could affect that timeline, the person said.