BEIJING (Kyodo) -- A Beijing court on Friday handed down a seven-year jail term to a former senior editor at a major Chinese newspaper affiliated with the ruling Communist Party who had been accused of leaking information to Japanese diplomats, sources familiar with the matter said.

Dong Yuyu, a former deputy head of the Guangming Daily editorial department, had pleaded not guilty to the charge and is set to appeal the court decision, the sources said.

He was detained in February 2022 after meeting with a Japanese Embassy official in Beijing and was indicted in March last year for alleged espionage, the sources said.

The Japanese diplomat who met with Dong was temporarily detained while on duty, with China justifying its action by saying he had engaged in activities "inappropriate" for his embassy job.

Japanese Foreign Minister Takeshi Iwaya declined to comment directly on the case at a press conference in Tokyo except to say activities by Japan's diplomatic missions overseas are "justifiable."

Chinese Foreign Ministry spokeswoman Mao Ning told a press conference that China's judicial body "strictly" deals with cases, adding crimes "will never fail to be punished according to law."

Dong, known as a liberal commentator, is a longtime friend of former Japanese Ambassador to China Hideo Tarumi and was invited to his residence for a Lunar New Year celebration in early 2021, the Chinese journalist's family has said.

The verdict named several individuals believed to be Japanese diplomats based in Beijing, referring to them as "agents of an espionage organization" and identifying the Japanese embassy as such, according to the sources.

His trial was closed to the public. In China, it is customary that allegations concerning national security are not released, and the details are not announced in most cases, even after rulings are finalized.

More than 60 people, including American journalist Bob Woodward and Tomoko Ako, a China studies professor at the University of Tokyo, had signed an open letter of concern over Dong's indictment, saying he faces a jail term for what they believe were "normal contacts with foreigners."

The former senior editor, who is not a Communist Party member, knew numerous Japanese and American journalists, scholars and diplomats. He was awarded fellowships at Harvard University and Keio University and was a visiting professor at Hokkaido University in Japan, according to Dong's family.