China hit out at campaigners in Taiwan for "playing up" the detention of its NGO worker Lee Ming-cheh, warning rights groups that any further criticism and questioning of Beijing will damage already tense relations across the Taiwan Strait.
"Any attempt to play up the case of a Taiwan resident under investigation will further harm the already severe relations between the mainland and Taiwan," Beijing's Taiwan Affairs Office spokesman An Fengshan told a news conference on Wednesday.
A former local activist with Taiwan's ruling Democratic Progressive Party (DPP), Lee Ming-cheh, 42, is the first overseas NGO worker known to be detained in China since a draconian law gave police control over foreign nongovernment groups at the beginning of this year.
He was detained by the ruling Chinese Communist Party's state security police on suspicion of "endangering national security" on his arrival in the southern border city of Zhuhai on March 19.
Chinese law allows police to detain those suspected of "national security" crimes and hold them under residential surveillance at a secret location for up to six months, with no access to lawyers or family visits.
In China's first formal response to questions and concerns over Lee's whereabouts and well-being, An confirmed that the community college manager and lifelong democracy activist is "being investigated for suspected activities that endangered national security."
"Some outside groups in Taiwan have taken the case to attack the mainland, make trouble, and interfere with the investigation," An said. "They will not be able to attain their goals."
"If they continue to deliberately make trouble and intentionally interfere with the case ... this will further complicate matters and damage the interests of the parties," he warned.
"If certain parties in Taiwan seek to link this case to the cross-straits relationship and make malicious attacks on mainland China, fanning the flames, all they will achieve is the worsening of what is already a seriously strained relationship," he said.
He gave no details of Lee's whereabouts, however.
"The investigation is being conducted in accordance with the law and the suspect's legal rights will be protected," An said.
No one has been attacking China
Beijing's statement comes after officials revoked the travel pass of Lee's wife Lee Ching-yu, preventing her from boarding a flight to the Chinese capital in a bid to visit her husband.
Lee Ching-yu was informed of the cancellation as she tried to board a direct flight from the democratic island to Beijing, having previously said she would try to "rescue" her husband.
She later told reporters she had earlier been warned off the trip by Chinese officials acting via "intermediary" Li Junmin, a former Taiwanese spy who spent 27 years in prison across the Taiwan Strait in mainland China.
Cheng Shiowjiuan, Lee Ming-cheh's boss at the Taipei Wenshan Community College, said nobody has been attacking China, however.
"In our opinion, the real damage to cross-straits relations has been done by the mainland, while has detained someone with no formal legal process and in breach of cross-straits agreements on family visits and other matters," she said.
"Everything that has been said here in Taiwan, whether it has come from civil society groups or relatives, has been based in fact," Cheng added.
Lawmakers from Taiwan's DPP and New Power Party (NPP) groups in the Legislative Yuan issued statement on Tuesday hitting out at Lee's detention.
"While Lee Ming-cheh’s family and nongovernmental organizations are exerting all efforts to save him, the government’s passiveness has left the family in a helpless state, and stirred public anger and concern," the statement said.
Legislative Speaker Su Jia-chyuan said Beijing's refusal to allow family visits "falls short of humanitarian standards," and called on officials to inform Lee Ching-yu of her husband's location.
NPP spokesman Lee Chao-li said An's news conference had changed nothing.
"They are still forbidding family visits, and they are still refusing to tell us where Lee Ming-cheh is," Lee Chao-li said. "This matter hasn't been conducted according to mutual information channels established across the Taiwan Strait."
"The Office of Taiwan Affairs has given no new details of the case, nor shown any change in its attitude," he said.
Reported by Wen Yuqing for RFA's Cantonese Service, and by Shi Shan for the Mandarin Service. Translated and edited by Luisetta Mudie.