BERLIN (Reuters) - A German court jailed a teenage German-Moroccan girl on Thursday for stabbing a policeman at a train station on the orders of Islamic State (IS) militants.

Safia S., a dual citizen aged 16, was convicted of attempted murder and being an IS supporter by a regional court in the northern city of Celle.

Her defense lawyer said he would appeal the six-year prison sentence, which he called “unquestionably high”, at the federal high court in the southwestern city of Karlsruhe.

The girl’s father, identified only as Robin S., told the newspaper chain RedaktionsNetzwerk that prosecutors carried out a “show trial” against his daughter because she was Muslim.

“If she had been a punk, she would have gotten a maximum of two years,” RND quoted the father as saying. He said the girl regretted her actions and that she deserved another chance.

Germany has been on edge over Islamist violence because of a spate of attacks over the past year, the worst being a truck that rammed into an outdoor Christmas market in Berlin on Dec. 19, killing 12 people.

During the trial, which began in October, Safia’s lawyer argued that she lacked the capacity to know she was doing wrong.

Prosecutors said Safia S. traveled to Istanbul in January last year where she met members of Islamic State, and that they planned to help her enter territory it controlled in Syria.

While in Istanbul, they said, she received orders to carry out a “martyrdom attack” in Germany, where investigators said they believe she was radicalized.

Safia’s father said the girl must have become radicalized very quickly. “You couldn’t tell anything. She was normal, like always,” he told RND. “She wore a head scarf, but she was also a fan of Justin Bieber and played soccer.”

Then aged 15, she stabbed and seriously wounded the policeman at the train station in Hanover in February after she was brought back to Germany by her mother, prosecutors said.

A now 20-year-old German-Syrian man, named only as Mohamad K., was sentenced to 2-1/2 years in prison as an accomplice after failing to inform police despite knowing of Safia’s plan.