File photo shows the office of Chinese Ministry of Foreign Affairs. [Photo: bcegc.com]

China has investigated a Japanese citizen on suspicion of threatening Chinese national security, confirmed the Chinese Ministry of Foreign Affairs on Saturday.

The foreign ministry has also informed the Japanese Embassy in China about the case.

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 out of touch since mid-July when he visited Beijing. It also stated the possibility that the man has been detained by China's national security authorities.