Kouts was arrested on the charges of espionage in September 2020.

"As the disclosure of court proceedings has been limited and part of the criminal case is still in closed proceedings, the prosecutor's office cannot currently disclose exactly what information Tarmo Kouts handed over to Chinese intelligence in the commission of crimes against the state," Inna Ombler, public prosecutor, was cited as saying by the Baltic News Service.

Reportedly, the court also confiscated 17,000 euro (a bit over $20,000) from Kouts as proceeds from the crime.

Kouts, a researcher in the Tallinn University of Technology, was previously a member of the scientific committee of the country's ministry of defense and a member of the scientific committee of NATO's Center for Maritime Research and Experimentation.

Estonia has convicted a maritime scientist who also worked at a Nato facility of spying for China, officials and media reports said on Friday, in the country’s first intelligence case not linked to Russia.

Tarmo Kouts was convicted and sentenced to three years in prison by Harju county court in Tallinn earlier this month at a hearing held behind closed doors.

The court also confiscated €17,000 (US$20,000) from the 57-year-old Kouts, a leading expert in oceanography who worked at Tallinn Technical University.