Story highlights Police are treating it as a "terrorist incident"

One person suffers serious injuries

The suspected attacker is in custody

(CNN) A man stabbed three people at an east London Tube station Saturday before police subdued him with a stun gun and made an arrest, London's Metropolitan Police said.

Police said they were treating the stabbing at Leytonstone station as a terrorist incident.

One man sustained serious injuries not considered to be life-threatening, police said. Two others suffered minor injuries.

The suspect was taken to a London police station.

Police said they were called just after 7 p.m. to reports of a number of people stabbed at the station and a man threatening others with a knife.

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