John Leung, who has permanent residency in Hong Kong, was detained in April 2021 in the southeastern city of Suzhou.

Details of the case against John Shing-Wan Leung, who also has permanent residency in Hong Kong, have not been publicly released.

He “was found guilty of espionage, sentenced to life imprisonment, deprived of political rights for life”, said a statement on Monday from the Intermediate People’s Court in the eastern Chinese city of Suzhou.

Suzhou authorities “took compulsory measures according to the law” against Leung in April 2021, it said, without specifying when he had been taken into custody.

It was unclear where Leung was living at the time of his arrest.

Such investigations and trials are held behind closed doors and little information is released other than vague accusations of infiltration, gathering secrets and threatening state security.

Nevertheless, such heavy terms are relatively rare for foreign citizens in China.

A spokesperson for the US embassy in Beijing said they were aware of reports that a US citizen had been recently convicted and sentenced in Suzhou.

“The Department of State has no greater priority than the safety and security of US citizens overseas,” the spokesperson said.

“Due to privacy considerations, we have no further comment.”

The government of Hong Kong, a former British colony that was returned to Chinese rule in 1997, also had no word on the case.

The court statement provided no further details on the charges, and closed-door trials are routine in China for sensitive cases.

Foreign ministry spokesman Wang Wenbin declined to comment further on the case at a regular news briefing on Monday.

US President Joe Biden is due to head to Japan for a meeting this week of leaders of the Group of Seven (G7) major developed economies.

The G7’s relationship with China is expected to be high on the agenda at the May 19-21 summit.

Other high-profile espionage cases in recent years include the arrest in 2019 of Chinese-born Australian writer Yang Jun.

Australia called last week for another of its nationals – jailed journalist Cheng Lei – to be reunited with her family after 1,000 days in detention over “supplying state secrets overseas”.

In April, authorities formally charged a prominent Chinese journalist with spying, more than a year after he was arrested while having lunch at a Beijing restaurant with a Japanese diplomat, a media rights group said.

China last month approved an amendment to its anti-espionage law, broadening its scope by widening the definition of spying and banning the transfer of any data related to what the authorities determine is national security.

The changes to the law will come into force on July 1.