Ammon News - Eighteen people were injured – four of whom remain in critical condition – in a knife attack Friday in the German city of Hamburg, authorities said.

Hamburg police said they have arrested a 39-year-old German woman, who they believe acted alone in carrying out the attack at the city’s Central Station, after a major police operation. She is in police custody and expected to be brought to a court on Saturday, police said.

Six people were “badly injured,” while seven others were “lightly injured,” the fire department said. Dozens of emergency services were active on the scene.

Police previously said that several people had sustained “life-threatening injuries” in the attack.

Investigations into the incident are ongoing.

In a statement late on Friday, Hamburg police said the attacker had acted “apparently indiscriminately, stabbed passersby, injuring some of them critically.”

“Further background and circumstances are not yet known. The investigation is being conducted intensively,” the police statement said, adding more information would be provided “as it becomes available.” CNN