Two Taiwanese police officers were "forcibly" taken from their accommodation and questioned about Taiwan’s critical infrastructure during a trip to China’s Fujian province in June, the Mainland Affairs Council (MAC) said Thursday, July 16.

MAC Deputy Minister Liang Wen-chieh (梁文傑) said at a news briefing in Taipei that one officer was serving and the other retired. Chinese state security personnel took them to another location and questioned them separately.

The Chinese authorities also examined the officers’ phones and asked about their current duties, families, and children. The officers had previously believed traveling to China did not pose any risks, but after the incident one of them asked MAC to warn public servants working at sensitive agencies not to go there, he said.

MAC said last week that it had received reports that 10 Taiwanese nationals had lost contact in China. On Thursday, Liang said four of those 10 were being detained, another was suspected of being detained, and the remaining five were still unaccounted for.