THE Chinese government has confirmed that it is holding a Taiwanese pro-democracy activist and is investigating him on suspicion of “pursuing activities harmful to national security”.

Lee Ming-che, 42, cleared immigration in the semi-autonomous Chinese territory of Macau on March 19 and never showed up for a planned meeting later that day with a friend in the mainland Chinese city of Zhuhai.

China’s Taiwan Affairs Office said Lee was in good health, but gave no information about where he was being held or other terms of his detention.

“Regarding Lee Ming-che’s case, because he is suspected of pursing activities harmful to national security, the investigation into him is being handled in line with legal procedures,” spokesman Ma Xiaoguang told reporters at a news briefing.

Amnesty International said Lee’s detention raises fears China is broadening its crackdown on legitimate activism, and urged the authorities to provide further details on his detention.

Lee’s “detention on vague national security grounds will alarm all those that work with NGOs in China. If his detention is solely connected to his legitimate activism he must be immediately and unconditionally released,” Nicholas Bequelin, the group’s east Asia director, said by email.

Responding to Ma’s comments, Taiwan’s Cabinet-level Mainland Affairs Council said repeated requests have been made to China through both official and private channels for information about Lee, but none has been forthcoming. It said he suffered from high blood pressure and other health problems, and asked that China “please provide the appropriate medical care and ensure his physical health”.

A colleague of Lee’s said he may have attracted the attention of China’s security services after he used the social media platform WeChat to discuss China-Taiwan relations. Cheng Hsiu-chuan, president of Taipei’s Wenshan Community College, said Lee used WeChat to “teach” an unknown number of people about China-Taiwan relations under the government of Taiwan President Tsai Ing-wen.