MIAMI >> The U.S. government has been paying to feed and shelter thousands of Cubans trying to migrate to the United States, in what critics consider another sign of the lopsided treatment provided to Cubans under U.S. law.

The Obama administration has tried hard to deter the crush of migrants arriving from Central America in recent years. It has pressed Mexico to crack down on migrants passing through its territory, while women and children who managed to cross the U.S. border have been held in detention facilities.

But U.S. law gives Cubans special status to live in the United States and apply for a green card, provided they make it here. That has set off a rush of Cubans who have taken advantage of changes inside Cuba that make it easier to leave, and who are worried that the Obama administration’s improved relations with their government will soon erase their privileged status.

In January, the United States pledged $1 million to help provide temporary shelter, potable water, food, sanitation and hygiene kits to thousands of Cubans who were stranded in Costa Rica while trying to make their way to the U.S. border.

Tens of thousands of Cubans have been arriving each year to the southwestern U.S. border after making an arduous journey by land through eight nations. But Nicaragua put a stop to the exodus by refusing them passage in November, causing a bottleneck of about 8,000 Cubans in Costa Rica and 3,000 in Panama.

The Costa Rican government was forced to open 29 shelters in schools, fire stations and other locations around the country where the Cubans are fed and sleep on mats on the floor. Some 2,000 Cubans remain.

The United States contributed to the effort through the International Organization for Migration, eliciting criticism that it was helping Cubans on their journey north at the same time it was blocking other migrants.

“We expect this particular contribution to be a one-time contribution, and the final amount that will actually be provided to IOM will depend upon needs on the ground, given that the number of vulnerable migrants in need of immediate humanitarian aid in Costa Rica fluctuates,” the State Department said in a statement.

The International Organization for Migration declined to discuss the donation, referring questions about it to the U.S. government.

“I don’t think that the ambassador wants to talk about exact amounts,” said Roeland de Wilde, who heads the organization’s mission in Costa Rica. “He wants to talk about the role, the impact and the fact there is support.”

The State Department said the donation was consistent with other U.S. efforts to help vulnerable migrants throughout Central America. The United States has spent hundreds of millions of dollars in Central America in aid programs for law enforcement and other areas, largely to stem the tide of migration.

“It’s a double standard for sure,” said Kevin Appleby, international migration policy director at the Center for Migration Studies in New York. “We are not doing that for the Central American children who are more vulnerable. We are not paying for their shelters in Mexico.”

The U.S. government, he noted, has paid Mexico to step up deportations.

“They are handling even more vulnerable populations by using tax dollars to interdict them versus housing others,” he said. “That’s the inconsistency they are embarrassed about.”

Aracy Matus Sanchez, who runs a refuge for migrants in southern Mexico, said that as far as she knew, none of the shelters in Mexico received American funding.

“It seems a little strange,” she said. “Here in Mexico, support has not been seen in any way. I suppose it makes sense they would receive the Cubans with open arms, because they are more educated.”

David North, a fellow at the Center for Immigration Studies, said any debate that arises over the donation boils down to questions about the Cuban Adjustment Act, the 1966 law that gives Cubans the right to enter the United States, even if they paid smugglers to make the journey.

The Cuban government has consistently pressured Washington to do away with the law, which many people feel encourages illegal and dangerous journeys by land and sea.

“I just don’t think we should be encouraging people by funding even this rudimentary shelter in Costa Rica,” North said.

Rep. Carlos Curbelo, a Republican in South Florida who has introduced legislation to eliminate welfare aid for Cuban migrants, said President Barack Obama was to blame for the migration crisis because he had normalized relations with Cuba, but Curbelo said the donation was important anyway to support a major partner in the region.

“Costa Rica has always been a key ally in the region and offered assistance to these Cubans after the Marxist government of Nicaragua shut its border in a geopolitical dispute,” Curbelo said in an email. “The following crisis exasperated Costa Rican resources as the migrants piled up in that country. Throughout, the Costa Rican people demonstrated great humanity and hospitality to these migrants.”

Manuel Gonzalez, the Costa Rican foreign minister, said his country had spent up to $3 million housing the Cubans. At one point, 29 shelters were open, although 15 have since closed as thousands of the migrants have left for routes to the United States in a deal brokered by Central American nations and Mexico.

“At one point, it was costing $35,000 to $40,000 daily,” Gonzalez said. “It’s complicated logistics: security, medicine, food, electricity. It’s quite an important daily expenditure.”

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