As President Trump makes threats against Cuba, former Defense Secretary Robert Gates said the biggest risk the Communist-ruled island poses to the U.S. is its potential collapse and a migration crisis to the U.S.

"The biggest risk is that we end up with another Mariel evacuation from Cuba that has tens of thousands of Cubans heading to the United States out of desperation," Gates said Friday in an interview with "Face the Nation with Margaret Brennan." 

Known as the Mariel Boatlift, about 125,000 Cubans sought refuge in the U.S. in 1980, as Cuba's failing economy led to dissent on the island. The mass exodus strained social services in Florida and led the state and federal governments to declare a state of emergency. 

Gates said Cuba's involvement in other events, such as providing security for ousted Venezuelan President Nicolás Maduro, has "impacted" U.S. national security, but questioned whether Cuba poses an "imminent threat" to the U.S. 

"Other than in these, if you will, peripheral ways, I think the main threat is, frankly, is collapse," he said. 

President Trump has threatened the possibility of military action against Cuba for months and Secretary of State Marco Rubio has called for economic and political reforms. 

The Trump administration has been trying to squeeze Cuba's economy by imposing an oil blockade that experts say has pushed the nation to its most dire state since the collapse of the Soviet Union, which heavily subsidized Cuba's economy. Cuba's energy minister said this week that Cuba has run out of fuel, largely as a result of the blockade.

CIA Director John Ratcliffe traveled to Havana on Thursday for a rare meeting with senior Cuban officials, an agency official told CBS News, delivering a message that the U.S. was prepared to expand economic and security engagement with Cuba if Havana "makes fundamental changes."