U.S. President Donald Trump on Thursday said he would see what he could do to help "save" detained Hong Kong media tycoon Jimmy Lai, even though Chinese President Xi Jinping would not be "thrilled."

Hailed by some as a hero and scorned by others as a traitor, Hong Kong's pro-democracy media tycoon Jimmy Lai is in the final stage of his national security trial. Closing arguments were scheduled to start on Thursday for Lai, who is accused of colluding with foreign forces under a Beijing-imposed national security law.

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.