A man injured five people, two seriously, in a stabbing attack in the heart of Amsterdam last week, and Dutch public prosecutors said Tuesday that they believe the suspect acted with “terrorist intent.”

Thursday’s knife rampage sparked panic in the streets of the Dutch capital with a police trauma helicopter landing on the city’s iconic Dam Square to treat the victims.

The 30-year-old suspect is from Donetsk in eastern Ukraine, and will remain in custody for at least two more weeks. He is suspected of “five counts of attempted murder or manslaughter with a terrorist intent,” prosecutors said in a statement.

Carrying multiple knives, the man attacked people seemingly at random in the streets around Dam Square before being overpowered by a British man, who has been hailed as a hero.

The victims were a 67-year-old woman and a 69-year-old man, both from the United States, a 26-year-old man from Poland, a 73-year-old Belgian woman and a 19-year-old woman from Amsterdam.

Four of the victims remain hospitalized but their condition is stable, the prosecutors said.

The attacker was himself wounded in the leg and transferred to the medical wing of a detention unit in The Hague, where he is now being held in solitary confinement.

He has not told authorities anything about his motives for the attack, although local media reported that he has confessed to the stabbings.

Amsterdam Mayor Femke Halsema thanked the British tourist, who has remained anonymous, for his “heroic act” that likely prevented more people being attacked.