Prosecutors in Germany on Thursday asked the high court in Celle in Lower Saxony to sentence the 16-year-old Safia S. to six years in prison. A lawyer for the joint plaintiff - another police officer - also demanded the same punishment for her. The proceedings are taking place behind closed doors, because Safia S. is a minor.

The defense was expected to present its arguments on Friday, news agencies reported. A judgment was expected on Thursday.

The German-Moroccan teenager is accused of injuring a 34-year-old policeman by stabbing him in the neck at Hanover's main railway station last year.  The officer ultimately survived life-threatening injuries.

A 20-year-old German man of Syrian origin, Mohamad Hasan K., was also accused of being her accomplice and planning a terror attack that led to a football game being canceled in Hanover in 2015. Prosecutors have demanded three years of juvenile detention for the man.

According to the prosecutors, the German schoolgirl of Moroccan origin had developed contacts with members of the "Islamic State" while on a trip to Turkey. She was then incited to carry out "martyr operations" in Germany. Initially she wanted to travel to IS-controlled areas in Syria on her own, but was discovered by her mother who brought her back to Germany.

Referring to the Safia S. case in a speech on Thursday, head of the German intelligence service, BND, Hans-Georg Maassen, said that the "Islamic State" was using online networks like Facebook for "headhunting" purposes. Nearly 200 recruits out of around 900 roped in by the IS in Germany to travel to fight in Iraq and Syria are women, he said. Some of them are just 13 or 14 years old, he added.

mg/rc (dpa, AFP, epd)

Editor's note: The original version of this article incorrectly reported that Safia S. had attacked a policewoman (the officer was male), and said that the officer was "fatally injured." While the injuries sustained were life-threatening, the officer survived them.