Four people have been injured in a knife attack at a Frankfurt train station. The perpetrator is reportedly on the run.

The attack occurred at Hauptwache station on Saturday (29 October) Mail Online reports.

The local police force tweeted: "There was a knife assault at the #Hauptwache in #Frankfurt. That's why so many colleagues [police officers] and rescue workers there."

Police have confirmed there are four victims who are receiving treatment in hospital for stab wounds. Their injuries are not believed to be life-threatening, Hessenschau reports.

The motive for the stabbings is not yet clear and police have urged the public to refrain from speculation.

Germany has suffered a spate of horrific knife attacks this year. On July 18 Pakistani teenager Riaz Khan Ahmadzai, 17, was shot dead by police after he attacked five passengers on a train in Wurzburg with an axe.

Four days later German-Iranian teenager Ali Sonboly shot nine people dead during a rampage through a shopping centre in Munich before taking his own life. It was reported that he was taking revenge for years of being bullied at school.

Two days later a Syrian refugee, 21, hacked a pregnant woman to death in Reutlingen. On the same night Daleel, 27, injured 12 people when he detonated a rucksack packed with metal shards and screws outside a wine bar.

It was revealed that he was intending to detonate a bomb at an open-air music festival, but was refused entry to the event by security guard Pascal Bohm.

The attacks have prompted fierce criticism of Chancellor Angela Merkel's open-door immigration policy.

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