Former Russian president Dmitry Medvedev, whose comments prompted US President Donald Trump to move two nuclear submarines, was once seen as a liberal reformer but has become one of the Kremlin's most prominent anti-Western hawks.In June, after the US launched air strikes on nuclear facilities in Moscow-allied Iran, Medvedev suggested that "a number of countries" were willing to provide Tehran with nuclear warheads, prompting an angry Trump to accuse him of "casually" threatening a nuclear strik