US President Donald Trump has said he is not optimistic about the release of former Hong Kong media boss Jimmy Lai Chee-ying, who was sentenced to 20 years for violating the national security law, after raising the issue with Chinese counterpart Xi Jinping during his visit to Beijing.

“[Xi] said Jimmy Lai is a tough one for him to do; he went through a lot, right or wrong, they went through a lot,” Trump told reporters on Air Force One during his return flight to the United States.

When asked whether the two sides had discussed human rights issues, Chinese foreign ministry spokesman Guo Jiakun said on Friday that Beijing had repeatedly stated its position on Lai’s case.

He said Lai was a key instigator and participant in anti-China and destabilising activities in Hong Kong.

“Hong Kong affairs are China’s internal affairs. The central government firmly supports the Hong Kong judiciary in performing its duties in accordance with the law,” Guo said.

Trump made the remarks following a highly anticipated two-day summit with Xi in Beijing, adding that the Chinese leader’s response regarding Lai’s release was not positive.