The young man had already been on the way to Frankfurt airport on Tuesday when the court decision was made, forcing the driver to turn around, according to media reports.
The European court’s ruling to block the deportation was not a final decision on the case itself, but rather was a way to ensure that the procedure would run properly as the court begins to consider the case, explained a court spokeswoman.
Germany’s own Constitutional Court just last week had already given the greenlight to such deportations of suspects dubbed Gefährder - a term used to describe potentially dangerous suspected terrorists - even if they have not been convicted of a crime.
In March, for example, authorities decided to deport two German-born men with Algerian and Nigerian citizenship who had been accused of planning a terror attack, though investigators ultimately could not find sufficient evidence to pursue criminal proceedings against them.
The men were still deemed to be dangerous and thus deported after police raids uncovered Isis flags, ammunition and weapons where the men lived.
The Constitutional Court also decided last week to allow the deportation of the Russian teen, who had spent nearly his entire life in Germany. Authorities accused him of being capable of planning a terror attack in Germany, arguing that he had sympathies with Isis as well as suicidal thoughts, and alleging that he had told another Islamist from Essen that he was ready to carry out an attack on civilians.
The law under which a so-called Gefährder may be deported allows interior ministries to send non-German citizens out of the country through an expedited process “to defend against a particular danger for the security of the Federal Republic of Germany, or against a terrorist risk.”
Though the law was first established following the September 11th 2001 attacks, it was not brought into full force until this year after the Berlin Christmas market attack in December.