The British police officer stabbed while subduing a suspect on New Year's Eve said Wednesday that "instinct took over" when he heard people screaming at a Manchester train station.

British Transport Police Sergeant Lee Valentine and several officers managed to bring down the knife-wielding suspect with a stun gun and pepper spray after he stabbed two people.

"We had no idea what we were running towards when we heard the screams on New Year's Eve," said Valentine, who is recovering at home from a stab wound to his shoulder. "When we saw the man wielding a knife, instinct took over."

Greater Manchester Police said Wednesday they are confident the suspect "acted alone in the final stages" of what police are treating as a terrorist act. They are still trying to determine if he had any support while planning the assault.

Police said the 25-year-old suspect has been detained under Britain's Mental Health Act, which means he is being assessed by mental health professionals and may be placed in a psychiatric hospital for treatment.

The suspect, who has not been named or charged, was shouting Islamist extremist slogans when he attacked two people at the Manchester Victoria station.

The train station is next to Manchester Arena, site of a May 2017 suicide bombing that killed 22 people at a pop concert.

Members of the suspect's family released a statement Wednesday saying they were "eternally grateful" for the swift response by emergency personnel and their "thoughts and prayers" are with the victims.

The family said the suspect "is being treated by specialist medical staff."

"It is important that the police investigation takes its course and any reports and articles avoid any assumptions, speculations and generalizations," the family statement said.

Two of the victims — a man and a woman — are still hospitalized with serious injuries. Police said the man is making "good progress" and should be released in the coming days while the woman is also making progress but is expected to be hospitalized longer.