The trial of a former Austrian army officer accused of spying for Russia over several decades opened in Salzburg Monday amid tight security -- and behind closed doors. The 71-year-old -- who has not been named -- faces charges of being part of a "structured state-run network of agents" and of betraying state secrets over a period of more than 20 years. He is suspected of having received around 280,000 euros (310,000 dollars) for his activities and faces up to 10 years in jail if found guilty. Press and public have been excluded from all but the first few minutes of the trial because of the sensitive nature of the evidence being presented. But the defendant's lawyer said Monday his client denied the charges and that he considered himself a patriot. Prosecutors say the information the defendant passed related primarily to Austria's weapons systems and the organisation of its land and air combat forces. They say he maintained contact with Russian intelligence into his retirement. At the time of his arrest Austrian media described him as a mid-ranking officer who worked in the defence ministry's planning department. Hearings in the case are expected to run until March 19. In July 2019 a European and international arrest warrant was issued for a Russian military intelligence officer named Igor Egorovich Zaytsev, thought to be the officer's handler. When the spying allegations against the officer were initially revealed, they provoked a row between Austria and Russia, with each country summoning the other's diplomats. Foreign Minister Karin Kneissl cancelled a trip to Russia. Since then diplomatic relations between Vienna and Moscow have largely been repaired. The affair was one of a series of cases in recent years where Moscow has been accused of espionage and even assassinations in EU states. One of the most notorious examples was the poisoning of former Russian double agent Sergei Skripal and his daughter in the UK in 2018. jsk/jj