A stabbing attack at the main railway station in the German city of Hamburg left multiple people injured on Friday.

Emergency services said 17 people were injured in the attack, though police later increased this number to 18.

Four people suffered life-threatening injuries and six were seriously injured, officials said.

Hamburg police said they had arrested a 39-year-old woman, a German national, near the scene of the crime on platform 13/14.  

Suspect thought to have 'acted alone'

"Based on the findings so far, we assume that she acted alone. Investigations into the background are in full swing," police said on X.

The police also do not believe that the stabbing was politically motivated, and appeared to be more of a random act. Investigators were looking into whether the suspect may have been mentally ill, police spokesperson Florian Abbenseth said.

The German national is set to be brought before a judge on Saturday, a police spokesman
told the news agency dpa, adding that the woman remains in police custody.

Germany's rail operator Deutsche Bahn has said train services to the station were disrupted by the police operation, warning of "delays and partial cancellations."

The attack occurred during rush hour at the station, which is one of the busiest in the country.

German Chancellor Friedrich Merz spoke by phone with Hamburg Mayor Peter Tschentscher and offered the federal government's assistance.

"The news from Hamburg is shocking. My thoughts are with the victims and their families. My thanks go to all the emergency services on the ground for their rapid assistance," Merz wrote on X.

Third knife attack in Germany this week

The incident is the latest stabbing in Germany in the past week.

Five people in their 20s were injured, four of them seriously, when a Syrian-born man attacked them in the early hours of Sunday morning at a bar in the western city of Bielefeld.

The 35-year-old suspect has been arrested and charged with four counts of attempted murder.

Federal prosecutors have taken over that investigation saying they believe the incident "was religiously motivated and is to be understood as an attack on the free democratic basic order." 

In Berlin, meanwhile, a boy, 13, was arrested on Friday after he allegedly stabbed a fellow 12-year-old pupil the day before at a school in the city's Spandau district. 

Edited by: Alex Berry