WASHINGTON — US President Donald Trump and Secretary of State Marco Rubio have issued new threats against Cuba, raising the specter of American military intervention in the country.The renewed threat takes on greater weight a day after a US court indicted the island’s former leader, Raúl Castro, over the 1996 downing of a plane.Rubio told reporters late on Thursday that Cuba has been a national security threat for years because of its ties to US adversaries Russia and China, while Trump said he is likely to be the president to finally take action.Trump said previous US presidents have considered intervening in Cuba for decades but that “it looks like I’ll be the one that does it.”“Other presidents have looked at this for 50, 60 years, doing something,” Trump told reporters when asked about Cuba during an environmental event in the Oval Office.The Trump administration has been raising the pressure on the communist-led island in an apparent bid to institute “regime change,” including a fuel blockade that has put the Cuban economy on the edge of collapse.The push has accelerated in recent days, with the US indicting Cuba’s former President Raul Castro and gathering military forces in the Caribbean.On Thursday, Adys Lastres Morera – sister of a high-ranking executive of the Grupo de Administracion Empresarial SA (GAESA) conglomerate, which is controlled by Cuba’s military and controls large swaths of the economy – was arrested.More sanctions were imposed on the Cuban government in the past week. The US military announced that several navy ships, including an aircraft carrier, had arrived in the Caribbean on Wednesday to take part in maritime exercises with partners in Latin America.Rubio, the son of Cuban immigrants who has long taken a hard-line against Cuba’s socialist leadership, said the Trump administration wants to resolve differences with Cuba peacefully but is doubtful the US can reach a diplomatic resolution with the island’s current government.Trump’s “preference is always a negotiated agreement that’s peaceful. That’s always our preference. That remains our preference with Cuba,” Rubio said in Miami before boarding a plane to attend a NATO meeting in Sweden and then visit India.“I’m just being honest with you, you know, the likelihood of that happening, given who we’re dealing with right now, is not high,” he said.Top Trump aides, including Rubio, CIA chief John Ratcliffe and other senior national security officials, have met with Cuban officials in recent months to explore possible improvements in relations. But the US side has come away unimpressed from those talks, leading to even more sanctions imposed on the Cuban government in the past week.When asked whether the US would use force in Cuba to change the island’s political system, Rubio repeated that a diplomatic settlement was preferred but noted that “the president always has the option to do whatever it takes to support and protect the national interest.”Federal prosecutors on Wednesday unveiled an indictment that accuses Castro of ordering the shootdown in 1996 of civilian planes flown by Miami-based exiles. The charges, which were secretly filed by a grand jury in April, included murder and destruction of an airplane.Cuban President Miguel Díaz-Canel has condemned the indictment as a political stunt that sought only to “justify the folly of a military aggression against Cuba.”