Chinese authorities have arrested a Japanese man in his 50s who was detained in December in Shanghai for violating the law, a Japanese government spokesperson said Wednesday, while calling for his early release.
"We have been strongly calling on the Chinese side for his early release at different levels and through various opportunities and will continue our efforts," Foreign Ministry spokeswoman Hikariko Ono told a news conference.
She said the man was arrested in June. It remains unclear to the Japanese side as to why he was arrested.
Since 2015, 16 Japanese citizens have been detained in China on various charges, including espionage. At least 10 have been indicted, and nine have received prison sentences of between three and 15 years.
The issue may heighten tensions between the two neighbors even as they mark in September the 50th anniversary of the normalization of their diplomatic ties.
Bilateral relations are already strained as Japan has lodged protests with China over repeated intrusions by Chinese coast guard ships into Japanese waters around the Tokyo-controlled, Beijing-claimed Senkaku Islands. China has also been intensifying military activities in and above waters near Japan.
A number of other foreign nationals have also been held in China, particularly after a counterespionage law and a national security law took effect in 2014 and 2015, respectively, under the government of President Xi Jinping, who came to power in 2013.