TAIPEI (Taiwan News) – The military will ask future recruits to sign a disclaimer stating they do not hold double citizenship, reports said Wednesday.

The Navy recently found that a sailor posted on a frigate held a Chinese ID that was obtained by his Chinese mother without his knowledge. 

The government had launched a probe into citizens illegally holding Chinese IDs or residency permits, questioning more than 30 people and investigating five companies allegedly helping with Chinese ID applications.

The Ministry of National Defense said it had assisted the Navy recruit, surnamed Yang (楊), in telling the National Immigration Agency that he wanted to keep his Taiwan citizenship. He was also transferred to a posting where he would not be able to receive sensitive information, per CNA.

In future, recruits will have to inform the military about any foreign passports, and sign a document confirming they do not hold foreign identity documents. Taiwanese nationals obtaining residency status in China do not have the right to join the military or take up public office in Taiwan, the ministry said.