BEIJING, April 12 (Xinhua) -- 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, an official said Wednesday.

Lee Ming-che is being investigated for suspected activities "endangering national security," An Fengshan, spokesperson for the Taiwan Affairs Office of the State Council, said at a press conference.

The mainland-based Association for Relations Across the Taiwan Straits has entrusted a Taiwan-based NGO to inform Lee's wife of the case and pass letters from him to his family, according to An.

"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 have a way to attain their goals."

"The investigation is being conducted in accordance with the law and the suspect's legal rights will be protected," An said, warning that attempts to interfere with the case will only complicate matters and harm Lee's rights.