A stabbing at a London Underground station is being treated as "terrorist incident," the London police said Saturday.
The London police counterterror command said in a statement that it is investigating the incident at Leytonstone Underground station in east London in which a man was threatening people with a knife at around 7 p.m. (1900 GMT; 2 p.m. EST). One person sustained serious injuries and two other received minor injuries.
One person was arrested. Police said a stun gun was used.
"We are treating this as a terrorist incident. I would urge the public to remain calm, but alert and vigilant," said Commander Richard Walton, who leads the counter-terrorism unit. "The threat from terrorism remains at severe, which means that a terrorist attack is highly likely.