The closing submissions in a national security trial against Hong Kong pro-democracy businessman Jimmy Lai were delayed on Friday after his lawyer said he had suffered heart palpitations.

Lai, 77, has pleaded not guilty to charges under Hong Kong's national security law of conspiracy to collude with foreign forces, as well as to a separate charge of conspiracy to publish seditious material. He has been held in solitary confinement for more than 1,500 days since December 2020.

Days before winning his second presidential term, Donald Trump made a bold promise: if he returned to the White House, he would free a pugnacious, self-made billionaire from a Hong Kong prison.