British police have charged a 29-year-old man with attempted murder following a “terrorist” knife attack at a London Underground station.

Counterterrorism officers were investigating the “violent unprovoked” attack at Leytonstone Underground Station that seriously injured one man late on Saturday, the Metropolitan Police said.

One unidentified man was arrested at the station and he remains in custody, while detectives were also “searching a residential address in east London”.

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The 56-year-old victim remains in a stable condition in hospital and his injuries are not believed to be life-threatening.

A second man was also injured, but did not require medical help.

“As a result of information received at the time from people who were at the scene and subsequent investigations carried out by the Counter Terrorism Command, I am treating this as a terrorist incident,” Commander Richard Walton, head of the counterterrorism force, said.

Local media quoted witnesses as saying the suspect was a tall, black man who may have had an Arabic accent.

He reportedly shouted “This is for Syria” before police used Tasers to subdue him.

Walton appealed for more witnesses to contact the police, after several video clips and photographs of the incident were posted online.