Amsterdam police say the man who stabbed five people in a seemingly random attack in the centre of the city on Thursday is a 30-year-old Ukrainian national from the Donetsk region.

Donetsk is in the east of Ukraine and largely under Russian control. The police did not say if he comes from the occupied area.

The man will appear in court on Tuesday for a remand hearing.

His motive is still under investigation, but public prosecution officers with experience in major crime and terrorism are involved in the probe. “There is reason to investigate all possible scenarios immediately,” the city’s chief prosecutor, René de Beukelaer, told local broadcaster AT5.

Identifying the man took some time because he was carrying several different identity papers when arrested, police say. He is also injured and is being treated at the prison hospital in Scheveningen under heavy security.

Four of the five people he is said to have stabbed – two older American tourists, a young Dutch woman, and an elderly Belgian woman – are still in hospital, and two of them were seriously injured in the attacks.

A Polish man was released from hospital earlier.

The police initially responded to reports of a mugging, but it soon became clear that several people had been stabbed. The suspect used several knives in the attacks.

He was apprehended by a British tourist who gave chase and sat on him until the police arrived. The tourist, who met Amsterdam mayor Femke Halsema on Friday, has said he does not want any publicity.

The suspect had been staying at a hotel on the nearby Damrak since March 26.