In an advisory, the U.S. Department of Homeland Security said that boaters planning to enter Cuban territorial waters must get permission from the U.S. Coast Guard or risk fines of $25,000 a day and 10 years in prison.

“It is illegal for boaters to depart with the intent to travel to Cuba for any purpose without a permit,” the advisory said.

Bringing foreign nationals into the U.S. illegally could be slammed with $250,000-a-day penalties and five years in prison, the department warned.

For more reporting from the Associated Press, continue below.

According to Osdany Veloz, an organizer of the boaters, the goal of next Monday’s planned trip is to go to international waters near the island, but not cross into Cuban waters, to let island residents know they have supporters in South Florida.

Organizers said they will set sail from South Florida if 100 boaters show up, according to Miami television station WFOR-TV.

“The purpose is to stay on the border, not trespassing, stay in international water and just let the Cuban people know we’re also fighting for their freedom, so once and for all they can be a free country,” said Jorge Lopez, who plans to make the trip.

Thousands of Cubans began taking to the streets last weekend to protest limited access to COVID-19 vaccines and basic goods. The country is going through its worst economic crisis in decades.

The protests in the island nation have sparked an outpouring of support in Florida, which is home to the nation’s largest community of Cuban exiles. Throngs of people in Miami, Orlando and the Tampa area have rallied in support, sometimes shutting down major thoroughfares.