Japan's Chief Cabinet Secretary Yoshihide Suga confirmed at a regular press briefing in Tokyo on May 22, 2017, that Chinese authorities have incarcerated six Japanese men since March on charges of espionage. He said “We were notified by China that three Japanese men each, six in total, had been detained in March by the Chinese authorities in Shandong Province and Hainan Province.” He added “We are providing them appropriate support through our diplomatic establishments abroad in light of protecting Japanese nationals." Both the provinces have big Chinese military bases. China’s Foreign Ministry confirmed the matter on May 22, saying the six were being held on suspicion of “illegal activities.” 

Ministry spokeswoman Hua Chunying told a regular news briefing that Japanese consular authorities had been informed of the investigation.v She said “According to what I understand, the relevant Chinese department is, in accordance with the law, investigating six Japanese citizens on suspicion of engaging in illegal activities in China.” She declined further comment.A source familiar with the matter said the three men detained Hainan are in their 20s to 50s and are suspected of being a threat to national security.