Outgoing Japanese Ambassador to China Hideo Tarumi expressed regret Monday for failing to help realize the release of a senior Astellas Pharma Inc. employee whom Beijing authorities have detained since March for alleged spying activities.

The envoy, who met with the detained Japanese national for the first time last week, said at a press conference that he did so just before finishing his three-year tenure to "offer a personal apology" and convey that Tokyo will keep working to realize his early release.

The man in his 50s was formally arrested in October on suspicion of espionage. Japanese Prime Minister Fumio Kishida reiterated his call for the citizen's release during a November summit meeting with Chinese President Xi Jinping in San Francisco.

Japanese Ambassador to China Hideo Tarumi speaks during a press conference at the Japanese Embassy in Beijing on Dec. 4, 2023, two days before his term as ambassador ends. (Kyodo) ==Kyodo

"We should not let this case be forgotten, so I met with him personally" to raise public awareness before leaving Beijing, the ambassador said.

The man, a former senior official of the Japanese Chamber of Commerce and Industry in China, was detained just before his scheduled return to Japan. The details of his alleged violation of counterespionage laws and the criminal code in China remain unknown.

Regarding the bilateral dispute over the ocean discharge of treated radioactive water from the crippled Fukushima Daiichi nuclear power plant, Tarumi called for experts and relevant authorities to discuss the matter and find a way to settle it as soon as possible.

In response to the Fukushima plant water release that began in August, China imposed a total ban on seafood imports from Japan. During their San Francisco meeting, Kishida said he and Xi agreed that the two countries will hold expert consultations on the issue.

With nearly 40 years of diplomatic experience, including assignments in China, Hong Kong, and Taiwan, the envoy emphasized the importance of communication between Tokyo and Beijing at various levels to stabilize their often strained ties.

Japan and China are "permanent neighbors, and we cannot move away" from each other, Tarumi said. "It is normal to have differences and frictions, and we should not fear that. But we should fear losing contact with each other."

The ambassador said stronger bilateral communication is more vital than ever when there are differences and frictions.

Tarumi is set to return to Japan this week. Japanese Ambassador to Indonesia Kenji Kanasugi is slated to replace him later in December.

Related coverage:

Japanese man's 12-year prison term over espionage finalized in China

Japan ambassador meets citizen detained in China over spying for 1st time

Japan, China reaffirm policy to settle Fukushima row via talks