A 32?year?old black British man and a 35?year?old British man of Caribbean descent were arrested by police on suspicion of attempted murder after a mass stabbing on a London?bound train in eastern England on Saturday.

Armed officers boarded the train at an unscheduled stop in the Cambridgeshire town of Huntingdon, and detained the pair within eight minutes of the first 999 emergency calls, which came at about 7:42 pm, according to police.

In total, 11 people received hospital treatment in Cambridge after the incident, with an update on Sunday confirming two remained in a life?threatening condition, while four had been discharged, reported the BBC.

Police stated the two suspects are in custody as they work to establish a motive, with officers saying there is no indication of a terrorist incident and appealing for witnesses to come forward.

The two men in custody have not been named, and there remained no update on the identities of the 11 injured by early Sunday afternoon.

The train had initially departed from Doncaster station in the north of England at 6:25 pm, bound for London King's Cross on a routine evening service, with witnesses saying it was dark and the train was not crowded.

About an hour later, soon after the train had departed from a scheduled stop at Peterborough station, the BBC quoted eyewitness Olly Foster hearing shouts of "run, run, there's a guy literally stabbing everyone", and saying that within minutes passengers were pushing through the carriage.

UK Prime Minister Keir Starmer said in a post on X: "The appalling incident on a train near Huntingdon is deeply concerning.

"My thoughts are with all those affected, and my thanks go to the emergency services for their response."

UK Home Secretary Shabana Mahmood said her thoughts are "with the victims, their friends and family" after last night's "horrific" attack, and expressed her "deepest thanks" to the police and fire services.

"They responded rapidly, with the utmost professionalism and saved lives," she said, paying tribute to the "exceptional bravery of staff and passengers on the train".

The BBC reported that police had initially used a national code for a potential "marauding terror attack", but that this was later rescinded.

John Healey, UK's defense secretary told Sky News that "the early assessment is that this was an isolated incident, an isolated attack".

In a statement given outside Huntingdon train station on Sunday morning, Superintendent John Loveless of British Transport Police said: "This is a shocking incident and my thoughts are with those who have been injured and their families."

"At 7:42 pm we were called to reports of a multiple stabbing on board the 6:25 pm LNER service from Doncaster to King's Cross.

"Officers immediately attended Huntingdon station alongside paramedics, where armed police from Cambridgeshire Police boarded the train and arrested two people within eight minutes of the first 999 call.

"We declared a major incident yesterday and counter terrorism policing were initially supporting our investigation. However, at this stage, there is nothing to suggest this is a terrorist incident.

"At this stage it would not be appropriate to speculate on the causes of the incident."