Police have arrested a man on suspicion of possession of a knife close to the Palace of Westminster.
Armed police were seen detaining the suspect near to the scene of the Westminster terrorist attack in March.
No one was reported injured in the incident. Police confirmed a Taser was discharged after the male appeared to reach for a knife.
The Carriage Gates entrance to Parliament were temporarily closed while police dealt with the incident.
A Met Police spokesperson said: "A man has been arrested near to the Palace of Westminster.
"At 11:10hrs on Friday, 16 June, officers on routine duties near to the Carriage Gates entrance to the Palace of Westminster became aware of a man acting suspiciously.
"The officers approached the man in order to speak with him. The man reached for a knife, and police discharged a Taser.
"The man - aged in his 30s - was arrested for possession of a knife.
"Nobody was injured. The arrested man has been taken to a central London police station, where he remains in custody."
Met Police previously arrested a man with a "backpack of knives" in Whitehall, close to the Houses of Parliament one month after the attack which left six people dead.