A German court convicted a military officer of espionage Monday for passing internal documents to Russia and offering more, and sentenced him to 3 1/2 years in prison, AP News reports.

The 54-year-old defendant, identified only as Thomas H. in line with German privacy rules, worked for the Federal Office of Bundeswehr Equipment, Information Technology and In-Service Support and had the military rank of captain. The Duesseldorf state court convicted him of espionage and violating official secrets.

The man acted of his own accord when he provided internal documents to the Russian consulate in Bonn in May 2023 to be forwarded to Russian intelligence, the court found. He also offered his cooperation and further documents from the German military, the Bundeswehr.

The court said the defendant, who had no previous convictions, had admitted to most of the case against him, cooperated with the investigation and regretted his actions. It also noted that he had significant health problems at the time.

The defendant testified last month that he had been motivated by fear of a nuclear escalation of the war in Ukraine, German news agency dpa reported. He said he had been following a pro-Russian influencer at the time and a social media post prompted him to approach the Russian consulate.

He told the court that he had severe burnout, was overworked and had suffered side effects from a COVID-19 vaccination.

The defendant said he applied for membership in the far-right Alternative for Germany party around the same time but later decided to leave.

The verdict follows a pair of recent arrests that underlined concern about Russian espionage in Germany, which is one of Ukraine’s leading weapons suppliers.

Two German-Russian men were arrested in mid-April on suspicion of espionage, one of them accused of agreeing to carry out attacks on potential targets in Germany including U.S. military facilities in hopes of sabotaging aid for Ukraine.