Britain’s capital woke up on Thursday to increased presence of armed police after an overnight knife attack left a woman in her 60s dead and five others injured in the busy central London area of Russell Square.
Scotland Yard arrested a 19-year-old man and said mental health was a “significant factor” in the case but terrorism was one line of inquiry.
Local residents said on Thursday that they had not seen such police presence since the July 2005 London bombings.
Assistant Commissioner Mark Rowley said: “This was a tragic incident resulting in the death of one woman and five others being injured. Early indications suggest that mental health was a factor in this horrific attack.”
The suspect was neutralised with a taser gun and was treated in a London hospital.
Police later said he has left hospital and is in custody at a south London police station.
The five injured included three women and two men.
“We are keeping an open mind regarding the motive and terrorism remains one line of inquiry being explored. As a precautionary measure, Londoners will wake up this morning to notice an increased presence on the streets of officers, including armed officers today. We would urge the public to remain calm, alert and vigilant,” Rowley said.
The attack comes within hours of Scotland Yard chief Bernard Hogan-Howe announcing a new operation to increase presence of armed police in London in the wake of recent terror attacks in Europe.
London mayor Sadiq Khan appealed to the people to remain calm and vigilant.
“We all have a vital role to play as eyes and ears for our police and security services and in helping to ensure London is protected,” he said.