On Sunday, Pope Francis called for Central American governments to help thousands of Cuban migrants stuck in Costa Rica as they attempt to journey to the United States.

"I invite the countries of the region to renew with generosity all necessary efforts in order to find a rapid solution to this humanitarian drama," the pope said in remarks to a crowd at the Vatican's St. Peter's Square.

Migration from Cuba to the United States has surged since a thawing of relations between the Cuban and U.S. governments late last year. Some Cuban migrants are concerned that the preferential treatment they currently enjoy under U.S. law, which gives them the right to remain if they reach U.S. soil, could soon change. By late September 2015, close to 30,000 Cubans had arrived at ports of entry along the Texas-Mexico border, according to the Houston Chronicle.

The journey from Cuba often begins with a plane ride to Ecuador, followed by an overland route through Central America. According to the Miami Herald, most of the migrants are between 20 and 40 years old and many are traveling with children.

In November, the Nicaraguan government stopped admitting Cubans making their way through the country to the U.S., leading to an estimated 5,000 of these migrants being stranded in neighboring Costa Rica, according to Reuters.

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