Miami, Florida - The US on Wednesday criminally indicted Cuba's former president Raúl Castro as Washington called on the communist-ruled island's people to embrace a "new path."

An indictment unsealed in a federal court in Florida charged the influential former president over the 1996 downing of two civilian planes manned by anti-Castro pilots.

Castro, brother of Fidel Castro, the late iconic US nemesis who led the 1959 communist revolution, was charged with murder, conspiracy to kill Americans, and destruction of aircraft.

The charges added fuel to speculation that President Donald Trump intends to topple the Cuban government.

Trump previously seized on a US domestic indictment to justify military action in January that toppled and abducted Venezuela's then-president, Nicolás Maduro, a staunch ally of the Cuban authorities.

Four people died in the 1996 downing of planes, sending relations plummeting. Two decades later, Raúl Castro joined then US President Barack Obama in an effort to reconcile.

But Trump reversed Obama's effort to improve relations.

Acting Attorney General Todd Blanche told a news conference in Miami that the US expects Castro to end up in prison, suggesting Washington could seize him if he does not surrender.

"For nearly 30 years, 30 years, the families of four murdered Americans have waited for justice," Blanche said. "The United States and President Trump does not and will not forget its citizens."

Cuban leader Miguel Diaz-Canel has slammed the new indictment, calling it a "political move with no legal basis."

The charges aim to "add to the file they are fabricating to justify the folly of a military aggression against Cuba," he said in an X post.

In a video message to Cuban people in Spanish, Secretary of State Marco Rubio, a Cuban-American, accused the Havana leadership of theft, corruption, and oppression.

"President Trump is offering a new path between the US and a new Cuba," Rubio said.

"A new Cuba where you have a real opportunity to choose who governs your country and vote to replace them if they are not doing a good job."