“Like elsewhere in the Florida Keys, the park has recently seen an increase in people arriving by boat from Cuba and landing on the islands of Dry Tortugas National Park,” the park service said in a statement announcing the closure to the public.

Cuba is experiencing a historic exodus of people fleeing the Communist-governed island nation amid extended economic hardship.

While most seek overland routes to the US through Central America and Mexico, others navigate the Caribbean Sea in makeshift vessels.

Park personnel had been providing food, water and basic medical attention until officials from the US department of homeland security could take over the relief effort, the statement said.

The park service said the closure would last several days.

In the meantime, ferry and seaplane services taking tourists to the islands were cancelled, and all other visitor services were suspended, the park service said.

The park is part of a small archipelago about 110km west of Key West, which itself is about 145km north of the closest part of Cuba.

The main island, which is dominated by the hexagonal Fort Jefferson, a disused military fortress made of brick, has no hotels and only a primitive campsite.

Tourists are required to provide their own food and water while visiting.

The US coast guard have reported they intercepted 6,182 Cubans at sea in fiscal year 2022, which ended on Sept 20, plus nearly 3,000 more from then until Dec 10.

A record 220,000 Cubans were caught at the US-Mexico border in fiscal year 2022.