TOKYO (BLOOMBERG) - A Japanese man in his 50s has been released from detention in China after completing a five-year prison sentence, Chief Cabinet Secretary Yoshihide Suga said.

The man had been detained since 2015 and officially given a prison sentence in 2018, Mr Suga said.

Kyodo News reported earlier that a 59-year-old, whom it did not name, had been serving a prison term for espionage, citing a government source.

Japan has denied that he was involved in spying, the report said.

He is set to return to Japan Thursday (July 2).

The release comes as ties between Japan and China have been strained anew by Beijing's clampdown on Hong Kong under a new security law that went into effect this week.

Nine Japanese have been indicted under separate Chinese espionage and security laws introduced in 2014.

The man moved to North Korea in the 1960s and later defected and returned to Japan. He was detained in 2015 close to the Chinese border with North Korea and sentenced to five years in 2018.