A 26-year-old Syrian Islamist has been charged with murder and attempted murder over two stabbing attacks in Germany, prosecutors said on Thursday.

The suspect, named only as Maan D., was a supporter of the Islamic State group who "decided to contribute to the worldwide jihad by killing alleged 'infidels' in Germany", they said in a statement.

On April 9, Maan D. allegedly attacked a man at random in the western city of Duisburg, stabbing him at least 28 times in the abdomen, head and neck.

The man died later the same day.

Less than two weeks later, Maan D. is accused of storming a gym in Duisburg in a bid "to kill as many 'infidels' as possible".

He allegedly attacked three male gym-goers in the locker room and shower area, leaving them with life-threatening knife wounds in their upper bodies.

He then also inflicted two stab wounds to the thigh of a first aider, the prosecutors said.

Islamist extremists have committed several violent attacks in Germany in recent years, the deadliest being a truck rampage at a Berlin Christmas market in December 2016 that killed 12 people.

More recently, a Syrian jihadist was given a life sentence in May 2021 for stabbing a German man to death and severely wounding his partner in a homophobic attack in the eastern city of Dresden.

The number of people on the Islamist extremist spectrum in Germany fell from 28,290 in 2021 to 27,480 in 2022, according to a report from the BfV federal domestic intelligence agency.

However, on presenting the report in June, Interior Minister Nancy Faeser said Islamist extremism "remains dangerous".