Associated Press

Maj. Gen. Lo Hsien-che was arrested last month on suspicion of espionage, but Taiwan offered no details.

 The Ministry of National Defense discovered suspicious activity last year and arrested Maj. Gen. Lo Hsien-che on Jan. 25, according to a statement posted on the ministry’s Web site late Tuesday. The statement did not give any details on what espionage activities the general might have been engaged in. He was recruited to spy for China sometime during a posting overseas from 2002 to 2005, the statement said.

 The Chinese government had no immediate comment on the case.

 Although Taiwan is a democratic self-governing island, the Chinese Communist Party in Beijing insists that it is part of China and is a “core interest,” meaning that China can use any means to defend its sovereign claims to the island. China strongly objects to American weapons sales to Taiwan and has broken off military dialogue with the United States over that issue. At the same time, under President Ma Ying-jeou, a member of the Kuomintang party, the Taiwanese government has been working with Chinese leaders to try to forge closer economic ties.  “Although the situation across the strait is easing, mainland China has never stopped spying on our military intelligence, and it’s being intensified,” the Taiwanese Defense Ministry said in the online statement. “Our military staff and civilians should be more alert and improve our awareness of unexpected incidents.”

Some newspapers in Taiwan reported that General Lo had been based in the United States when he was recruited by China, but a military official said at a news conference in Taipei, Taiwan’s capital, on Wednesday that the general was working in Thailand when he fell under the sway of China, according to a report by the official Central News Agency.

China has more than 1,000 missiles along its southeast coast aimed at Taiwan, which was occupied by the Kuomintang military when it retreated to the island after the Communist takeover of China in 1949. Before Mr. Ma took office in 2008, tensions between Beijing and Taipei ran high, after the Democratic Progressive Party enacted policies that appeared to move Taiwan closer to formal independence.

 Zhang Jing contributed research.