Six Japanese nationals are under investigation by Chinese authorities on suspicion of violating Chinese laws, Foreign Ministry spokeswoman Hua Chunying said on Monday in response to a report about alleged Japanese spies caught in China.

During a regular news conference Hua was asked to confirm the reported detention of six Japanese citizens alleged to be harming national interests.

China has reported the issue to Japan's consulate authorities in China, she said.

According to a report in Japan's Nikkei newspaper, the six were detained by Chinese authorities in East China's Shandong province and South China's Hainan province in March, suspected of alleged espionage, the report said.