Cuban migrants in US
Cuban migrants take a photo in front a U.S flag after arriving by plane from Panama to Mexico, as they make their way to the U.S., in Ciudad Juarez, at the Mexican border crossing with El Paso, Texas, May 17, 2016. REUTERS/Jose Luis Gonzalez

At least 540 Cuban refugees have tried to enter the U.S. through maritime routes so far in December, according to the U.S. Coast Guard.

Since Saturday, the Coast Guard intercepted 136 Cubans trying to reach U.S. illegally through the Strait of Florida, the agency said in a statement Wednesday. The asylum-seekers were intercepted in eight different operations.

Cubans refugees who reach U.S. soil are allowed to stay in the country under the “wet foot, dry foot policy.” Those intercepted by American authorities at sea are usually repatriated to Cuba. U.S. officials have expressed concern that likelihood of the policy ending has led to a surge in Cuban asylum-seekers.

A total of 51 people reached the U.S. successfully in the Florida Keys last weekend. The first group of 11 refugees landed in the upper Keys in Tavernier, the second group of 22 asylum-seekers arrived north of Key West and a third group of18 landed about 25 miles away on Big Pine Key.

"It is not uncommon to see a surge in Cuban migrant flow during the winter months when there are no major storms," Capt. Mark Gordon, chief of enforcement for the Coast Guard 7th District, said in the statement.

"We continue to strongly discourage attempts to illegally enter the country by taking to the sea. These trips are extremely dangerous. Coast Guard missions and operations in the Southeast remain unchanged and the Coast Guard and our partner agencies remain ready to stop those who take the illegal, ill advised and unsafe journey across the Florida Straits," Gordon said.

The number of Cubans seeking refuge in the U.S. has increased this year, according to Coast Guard. In the fiscal year 2016, 7,411 Cuban asylum-seekers were intercepted as opposed to 4,473 in 2015.

The December data on the interception of the refugees also comes within a month of Cuban revolutionary Fidel Castro’s death on Nov. 25. He died at the age of 90 due to failing health.