German authorities on Thursday announced the arrest of an 18-year-old German national, for allegedly planning to carry out an Islamist-inspired terror attack in Frankfurt.

The public prosecutor's office in Frankfurt and the Federal Criminal Police Office in Wiesbaden said that the suspect — who is of Moroccan descent and who grew up in Germany — had also intended on traveling to Iraq to join the co-called "Islamic State" (IS) terror group.

Investigation launched in summer of 2022

According to a joint statement, the man from the Hochtaunus district in Hesse, had been under investigation since August 2022.

Police accuse the suspect of planning an attack using an automatic weapon in Frankfurt, with the intent of harming as many people as possible.

Authorities say the man also allegedly researched the construction of explosive and incendiary devices on online and had made inquiries about the use of remote detonation mechanisms.

He had also obtained a long stabbing weapon, which he kept in his parents' garage.

In August 2022, a search warrant was executed at the suspect's home, during which computer storage devices were seized. 

Media stored on these devices included images of the "Islamic State" flag and "ideologically charged images of fighting and executions," according to the joint statement.

Investigators said they did not arrest the suspect at that time because there was no concrete evidence the suspect was planning an Islamist terror attack.

Arrest made as suspect attempted to leave Germany

Authorities believe the man postponed his plans to carry out the attack in Frankfurt, due to fear of being discovered. They also believe he had failed to get hold a firearm because of a lack of funds.

It is then believed the man planned to leave for Iraq on March 8, 2023 to join IS, or at least what little remains of the "Islamic State" in Iraq.

Police swooped on Wednesday as the man traveled by car in the direction of the German-Austrian border. Special units of Frankfurt police took him into custody at a freeway service area near Passau.

He is due to appear before a magistrate in Frankfurt on Thursday.

kb/msh (AP, dpa)