Taiwan resident Lee Ming-che, who is under investigation for endangering national security, was "in good physical condition", the State Council Taiwan Affairs Office said on Wednesday.

Lee was detained on suspicion of jeopardizing national security, and some groups in Taiwan have used the case to stir up trouble, the office said earlier this month.

He is in good physical condition and is being given good medical care, said Ma Xiaoguang, spokesman for the State Council Taiwan Affairs Office, at a regular news briefing on Wednesday.

"Lee's medical needs have been taken care of. He has also written a letter explaining the situation to his family," Ma said.

The suspect's legal rights are being protected during the investigation," Ma said.

The mainland has always encouraged exchanges between people from both sides of the Straits and has issued mainland travel permits for Taiwan residents, Ma said, adding that every year more than 5 million Taiwan residents visit.

During the briefing, Ma also urged the Taiwan authorities to adhere to the 1992 Consensus.

The mainland has always maintained hope that the two sides will adhere to the 1992 Consensus, which serves as the foundation of cross-Straits relations. However, the relationship changed on May 20, when the Democratic Progressive Party in Taiwan denied the consensus, Ma said.

"If the Taiwan authorities sincerely want to restore the communication mechanism across the Straits, they should return to the common political ground - the 1992 Consensus," he said.

Ma also confirmed the upcoming visit to the mainland of Lien Chan, former chairman of the Kuomintang in Taiwan, and said he is expected to meet Zhang Zhijun, head of the State Council Taiwan Affairs Office.

When asked about a mainland citizen who left his tourist group while traveling in Taiwan earlier this month, Ma said the tourist has returned to Xiamen, Fujian province.

"The related mainland tourism authority and travel agency have conducted investigations on the tourist and the tour group leader," he said.

Ma urged mainland tourists to observe a revised regulation on travel in Taiwan, which was made public on April 13.