China has acknowledged it detained a former Taiwanese ruling party worker for alleged involvement in activities that threaten national security.

A former member of the ruling Democratic Progressive Party in his 40s remains missing since he travelled from Macau to Guangdong, southern China, on March 19th.

A human rights group in Taiwan says the man follows human rights issues in mainland China, and has been posting remarks on democratization in Taiwan.NHK

Taiwanese officials have been asking Beijing to reveal the man’s whereabouts.

A spokesperson for China’s Taiwan Affairs Office said at a news conference on Wednesday that the man is suspected of endangering national security and remains under investigation.

Beijing didn’t specify the activities he has been allegedly involved with or where he is detained.

China has halted dialogue with Taiwan since the president of the Democratic Progressive Party, Tsai Ing-wen, expressed disagreement with the “one-China” principle.