London, January 1: The stabbing of three people - including a police officer - at a busy railway station in the heart of Manchester in the UK on New Year's Eve is being treated as a terror related incident by Britain's counter-terrorism officers, police said on Tuesday.

A 25-year-old man arrested on suspicion of attempted murder remains in custody after two knives were recovered at the scene. The knife-wielding man was caught on camera being tackled by security officials at Manchester Victoria station before being arrested.

Some eyewitnesses reported hearing him shout "Allah" during the attack on Monday night.

"We are treating this as a terrorist investigation which is being led by counter terrorism officers with support from Greater Manchester Police," said Chief Constable Ian Hopkins of Greater Manchester Police (GMP).

"They were working throughout the night to piece together the details of what happened and to identify the man who was arrested," he said.

The police chief said that officers are conducting a search at a property in Cheetham Hill area of north Manchester, believed to be the most recent address of the suspect tackled and arrested by officers at the scene.

He said the proximity of the latest terror attack site to Manchester Arena, where a suicide bomber had killed 22 people at an Ariana Grande concert in May 2017, made the latest incident all the more “dreadful”.

"Our work will continue to ensure we get to the full facts of what happened and why it took place," Hopkins added.

The force had declared the attack a "critical incident" in the immediate aftermath but added there was "no intelligence to suggest that there is any wider threat at this time".

British Prime Minister Theresa May tweeted her gratitude to the emergency services for their response to the attack.

"My thoughts are with those who were injured in the suspected terrorist attack in Manchester last night. I thank the emergency services for their courageous response," she said.

A man and woman, in their 50s, sustained "serious" but non-life-threatening injuries. Police said the woman had injuries to her face and abdomen and the man had injuries to his abdomen.

Earlier, British Transport Police (BTP) had said it is keeping an “open mind” on the motive behind the incident at a busy railway station in the north-west of England.

In an update, BTP's Assistant Chief Constable Sean O'Callaghan said the GMP had now taken over the investigation and expressed his pride in the four BTP officers who were immediately on scene to detain the man who was wielding a knife.

He said: "They were fearless, running towards danger and preventing further harm coming to passengers. Unfortunately, however, one of our police officers suffered a stab injury to their shoulder and we're all relieved that this is not more serious.

“It is good news that he has now been discharged from hospital, we are all wishing him a speedy recovery."

He reassured the public that incidents like these are “incredibly rare” and that BTP officers remain on duty throughout the national rail network. Officers first on the scene used a Taser gun to control the screaming knifeman and also a pepper spray before restraining and leading him away.

The New Year fireworks display at Albert Square nearby went ahead as scheduled for midnight.