LONDON — A mass stabbing attack that caused fear and chaos on a London-bound train in eastern England was not a terrorist incident, British police said on Sunday, adding that two men — both British nationals — had been arrested.

The attack occurred on Saturday evening on the typically busy service between the town of Doncaster, in northern England, and King's Cross station in the capital.

Bloodied passengers spilled out of the long-distance train when it made an emergency stop in the town of Huntingdon, where dozens of police waited, soon after multiple stabbings were reported onboard.

Two people were arrested by armed officers at the station. Police have not identified the suspects or disclosed a motive.

"Ten people have been taken to hospital with nine believed to have suffered life-threatening injuries," British Transport Police said in a statement on Sunday. "This has been declared a major incident and Counter Terrorism Policing are supporting our investigation whilst we work to establish the full circumstances and motivation for this incident."

The police force said that "Plato", the national code word used by police and emergency services when responding to what could be a "marauding terror attack", was initiated. That declaration was later rescinded, but no motive for the attack was disclosed.

"We're conducting urgent inquiries to establish what has happened, and it could take some time before we are in a position to confirm anything further," Chief Superintendent Chris Casey said.

"At this stage, there is nothing to suggest that this is a terrorist incident," Superintendent John Loveless from British Transport Police told the media on Sunday.

British Prime Minister Keir Starmer said the "appalling" incident was "deeply concerning". Starmer said his "thoughts are with all those affected".

London North Eastern Railway, which operates the East Coast Main Line services in the UK, confirmed the incident had happened on one of its trains and said there would be major disruptions on the route until Monday.

Knife crime in England and Wales has increased since 2011, according to official government data.

While Britain has some of the strictest gun controls in the world, rampant knife crime has been branded a "national crisis" by Starmer.

His Labour government has tried to rein in the use.

Nearly 60,000 blades have been either "seized or surrendered" in England and Wales as part of government efforts to halve knife crime within a decade, the interior ministry said on Wednesday.

Two people were killed and others were wounded in a stabbing spree at a synagogue in Manchester at the start of October in an attack which shook the local Jewish community and the country.

A man appeared in a London court on Thursday, charged with murder after a stabbing attack in broad daylight, which left one dead and two injured.