Gen Schwartz’s comments appeared to have enraged Mr Castro, who accused the United States of imperial Machiavellianism and claimed that Washington was bent on Cuba’s destruction.

So far, the reports of a Russian presence on Cuba remain speculative, with the Kremlin issuing a denial and the White House refusing to comment.

Even so, the speculation is mounting since Izvestia, often used to float controversial Kremlin plans, quoted military sources as saying that the proposal was in retaliation for US plans to build a missile defence shield in central Europe, ostensibly against a nuclear strike by Iran.