China detains Japanese national over security concerns

China has investigated a Japanese citizen on suspicion of threatening Chinese national security, official media here said.
The Chinese Ministry of Foreign Affairs has also informed the Japanese Embassy here about the case, state-run China Radio International reported.
Previously, Japan's Kyodo news agency cited a Japanese government official saying that a man involved in a Sino-Japan exchange group had been detained in China.
According to the Japan News Network, a leader of a Sino-Japan exchange group was missing since mid-July when he visited Beijing. It also stated the possibility that the man had been detained by China's national security authorities.