Counter-terrorism police in the U.K. on Sunday investigated a stabbing at a London Underground station in which a man brandishing a knife injured two people and reportedly said "This is for Syria."

Police arrested a 29-year-old man late Saturday and said they are treating the attack at east London's Leytonstone subway station as a "terrorist incident."

Richard Walton, chief of Scotland Yard's counter-terrorism command, said the decision was made because of information received from witnesses and subsequent police investigations. The force said it was searching a residential address in east London, but declined to say whether they were looking for other suspects.

British media reported that the suspect linked his actions to Syria after the attack. The claim could not be independently verified, but the incident comes just days after Parliament approved British airstrikes on ISIS targets in Syria.

The last extremist attack in the U.K. was in May 2013, when two British-born, al-Qaeda-inspired extremists stabbed an off-duty soldier to death on a busy London street.

In Saturday's attack, one man suffered serious knife injuries and was in the hospital in stable condition. Another man received minor injuries, while a woman was threatened but not hurt.

Video shot by witnesses at the scene showed a pool of blood on the station's floor as the suspect was seen lunging at several police officers who tried to subdue him. He was then pinned down after a stun gun was used.

One bystander can be heard shouting at the suspect: "You ain't no Muslim, bruv." The phrase, using slang for "brother," was quickly picked up by Twitter users who turned it into a trending hashtag #YouAintNoMuslimBruv to show their contempt for the suspect and extremism.

The suspect remained in custody at a police station Sunday.