HAVANA — The U.S. government on Thursday slapped new sanctions on Cuba in a fresh push to strangle the island’s economy and deepen its multiple crises. Among those hit with sanctions are Fidel Ernesto Castro, grandson of former President Raúl Castro, and Cuba’s Oil Industry Supply Import Company, known as Abapet. The company is responsible for importing special equipment and spare parts needed to sustain Cuba’s crumbling power grid. The sanctions aim to push Cuba’s critical machinery offline and exacerbate its energy crisis, said Brett Erickson, a sanctions expert and managing principal at Obsidian Risk Advisors, a consulting firm. “The U.S. is trying to really tighten the screws as much as possible,” he said. “The Trump administration seems to have no seriousness to accept any change from Cuba other than a toppling of regime. Marco is not going to let that go,” he added, referring to U.S. Secretary of State Marco Rubio. Erickson anticipated that Cuba’s government would try to circumvent the sanctions “because they have to.” “They’ll get creative in how they tr