Four people were injured in a stabbing attack at a train station in Frankfurt city center on Saturday.

Frankfurt police spokeswoman Chantal Ench said the attack took place inside the Hauptwache station during the afternoon.

She said all four victims were taken to hospital but did not provide further details.

Police said they were investigating how many perpetrators were involved in the attack.

Following the incident, Frankfurt police tweeted "There has been a knife attack at the Hauptwache in Frankfurt. That is why so many colleagues and rescue services are there," followed by "Four people were injured during a stabbing incident in Frankfurt. All four are currently in hospital."

The police also urged the public to refrain from speculating about the incident, reassuring them that there was no threat of further danger.

Security alerts

While Germany has been spared large-scale terror attacks, the country has been hit by a number of incidents in which asylum seekers - some linked to the "so-called "Islamic State," (IS)" - have carried out attacks.

Last summer, a 17-year-old Afghan refugee in Würzburg attacked passengers on a train with an axe, injuring five, while 15 people were injured at a music festival in Ansbach after a Syrian refugee blew himself up.

Earlier this month, the town of Chemnitz was on lockdown after police raided the apartment of 22-year-old Syrian refugee Jaber Albakr. After his capture and arrest on suspicion of planning an attack on a Berlin airport, Albakr committed suicide in his jail cell.

dm/jm (AP)