The first defendant to appear in court on Tuesday is charged with belonging to a terrorist organisation, as well as heading up a criminal gang. Eight other suspects will be tried for belonging to a terrorist organisation and making false statements during police questioning.
The man who has been identified as the main suspect, a Vienna-based radical Islamist preacher, will appear in court on February 22nd charged with various terrorist offences, including murder.
All 13 suspects were arrested during police raids in Vienna, Graz and Linz which involved some 900 police officers. The raids followed a two-year investigation into several people suspected of recruiting young people to fight in Syria.
Journalists have had to apply for accreditation to cover the trials and film and audio recording is prohibited in the courthouse.
Austria, a majority Catholic country, has seen dozens of its citizens join the jihadist cause in Syria or Iraq, sparking concerns about the national security threat posed by those who return from the war-ravaged countries.