US Secretary of State Marco Rubio said on Thursday that a "negotiated diplomatic settlement" with Cuba was unlikely, and President Donald Trump has the right and obligation to respond to perceived threats to national security.
Mr Rubio's comments come amid heightened tension between the US and Cuba in the months following the toppling of Havana's main regional ally, Venezuelan leader Nicolas Maduro, in January and an ongoing American oil blockade of the island.
"The President's preference is always a negotiated agreement," Mr Rubio told reporters. "I'm just being honest with you, you know, the likelihood of that happening, given who we're dealing with right now, it's not high."
Asked whether the US was planning military action against Cuba, Mr Rubio said that Mr Trump has "not just has the right, he has the obligation" to address threats to national security issues.
He described Cuba as "one of the biggest sponsors of terrorism for the entire region", saying there was a presence of Russian and Iranian intelligence as well as weapons on the island.
A recent Axios report quoting US officials said that Cuba had acquired 300 drones from Russia and Iran, with which it planned to attack the US base at Guantanamo Bay. Cuban leadership said the island is not a threat.
On Thursday, the US announced criminal charges against Cuban leader Raul Castro, brother of 1959 revolutionary figure Fidel Castro. The charges include murder and conspiracy to commit murder of American citizens.
With the US and Iran in an uneasy ceasefire, the Trump administration has shifted its focus back to the Western Hemisphere and has been intensifying its rhetoric against Cuba. The two countries have been at odds since Cuba's communist revolution in the 1950s, and the island is under what the US describes as an "embargo" that was expanded to include oil after the fall of Mr Maduro.
Cubans already facing scarcity of daily staples are now going hours a day without electricity as fuel supplies dwindle.
