A teenage ISIS supporter scouted out some of Germany’s most iconic buildings and monuments for a prospective attack, officials have said.
The 19-year-old Syrian man, who has not been identified, was arrested in March for suspected links to the so-called Islamic State after the alleged plans were uncovered.
Judges at the Federal Court of Justice ruled the man could be held for three more months to allow investigators to continue their work on Thursday, amid fears he could be part of a wider network plotting terror attacks.
In its decision, the court said the suspect had scouted out sites including the Brandenburg Gate, Reichstag parliament building and Alexanderplatz square for potential attacks over several months.
Having arrived in Germany as an asylum seeker in August 2015, he was believed to have been gathering detailed information for Isis until February this about the number of people and tourist buses in different areas.
A court document said intelligence was transmitted to an Isis contact in Syria using a smartphone.
Through electronic messages he also offered to act as a contact for potential attackers in Germany, “commit a non-specified attack” himself “or alternatively with two unknown people” officials said.
Investigators examined four mobile phones and data cards seized during his arrest, and had so far reviewed more than 37,000 text messages and chats, nearly 13,000 visual images and around 9,800 video images, according to the court document.
Investigators believe the man had worked with Isis in Syria since 2013, and maintained contact with the jihadist group using his mobile phone after arriving in Germany.
He also planned to return to Syria, where his parents, wife and son still live, to fight in the conflict there, according to the court document.
Another Syrian man, Jaber al-Bakr, was arrested on suspicion of planning a major bombing at a Berlin airport in October but killed himself in prison days later.