A former deputy chief of the government agency in Taiwan that handles relations with the mainland is under investigation for alleged breaches of national security.
The Mainland Affairs Council and the Ministry of Justice's Investigation Bureau had evidence against Chang Hsien-yao, a spokeswoman for the council, said yesterday, without giving details.
The two agencies were continuing their investigations, she said. One of the Investigation Bureau's roles is counter-espionage.
The council announced on Saturday that Chang had resigned for family reasons, but said the next day that he had been sacked and that unspecified allegations about his work were under investigation.
Chang sent text messages denying any wrongdoing, the Central News Agency reported.
Media reports on the island suggested that Chang might have leaked classified information in negotiations with the mainland.
The United Daily News quoted an unnamed government official as saying that the investigation could be connected with "leaking secrets", including the Taiwanese government's bottom line in talks with Beijing.
Observers said Chang's removal could complicate Taiwanese President Ma Ying-jeou's efforts to improve relations with the mainland, which have already been hampered by massive student-led protests in Taipei earlier this year against closer economic ties.
"The incident might have a negative impact on cross-strait ties when mutual trust between the two sides is fragile," said Chang Ya-chung, a politics professor at National Taiwan University.
Li Fei , a mainland-based Taiwan affairs expert at Xiamen University, said cross-strait consultations would continue despite Chang's case.
It would "have some impact on cross-strait relations, but will not change the direction of peaceful and friendly ties", Li said.
"Cross-strait relations will continue to develop."
Agence France-Presse, Kyodo