Everything We Know About the Russell Square Stabbing

A 19-year-old man is being held on suspicion of murder after a woman was killed and five others injured during a stabbing spree in central London. The potential terrorist attack happened in a central London tourist hot spot in Russell Square.

The attack was launched at 10.30pm on Wednesday a short walk away from the British Museum. Police arrested a man at the scene after stunning him with a taser. He is now being held on suspicion of murder in a south London police station after receiving treatment in hospital. The victim is a woman who is believed to have been in her 60s and has not yet been identified.

The Guardian has reported that guests in the Imperial Hotel right by the incident described hearing screaming from the square below, while witnesses to the aftermath saw a body lying on the floor as armed police arrived. Other accounts suggested the attacker was wearing a motorcycle helmet. Britain's most senior counter-terror officer, Mark Rowley, said early reports suggested mental health was a factor but terrorism remained a serious possibility.

Two women and three men suffered "various injuries" in the incident and were receiving treatment in hospital. Three were discharged Thursday morning.

One witness to the aftermath, Philippa Baglee, said she arrived at the scene to see, "someone lying on the ground and lots of people around and a guy with a black motorcycle helmet balanced on top of his head walking around. He was on the outside of everyone looking on the ground. The moment I saw an ambulance and police car arrive, I thought someone had just been knocked off their bike."

When describing the man, she said he was short and dressed in what may have been all black leathers.

She added: "It was all very calm. No one was panicking."

Police received the first call just after 10.30pm and arrived at the scene after five minutes. The investigation was led by murder detectives with the support of counter-terrorism officers.

Rowley, who addressed the public at 3.30am outside Scotland Yard, said extra police patrols would be on London streets following the attack. These will include armed officers in an attempt to reassure the public. "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," he said.

Scotland Yard had announced earlier on Wednesday that an extra 600 armed officers were being deployed on patrol in London after recent terror attacks in France and Germany.