Police said that the assailant was apparently mentally disturbed and not ideologically driven to go on a rampage, Deutsche Welle reports.
One woman was fatally wounded and another five people were injured in the knife attack in London’s Russell Square, which is close to the British Museum and the University of London.
Police were called to Russell Square at 10:33 p.m. local time (2133 UTC) after reports of a man seen in possession of a knife injuring people.
Police used a Taser to arrest the suspect, who officials said was a 19-year-old Norwegian national of Somali origin.
The female victim – an unnamed US citizen – was treated at the scene but was pronounced dead a short time later.
Police said mental health problems were likely the trigger rather than any radicalization or affiliation with a violent religious group.
Assistant Commissioner Mark Rowley says the investigation “increasingly points to mental health issues” as the explanation in the absence of any other apparent motive.
The nationalities of the injured were British, Israeli, Australian and a second American. None of the injuries appeared life threatening, police said.
Extra police have been deployed in the area.
London Mayor Sadiq Khan urged people to remain calm and vigilant.
“I urge all Londoners to remain calm and vigilant. Please report anything to the police. We all have a vital role to play as eyes and ears for our police and security services and in helping ensure London is protected,” he said in a statement.
The attack came on the same day that police announced that more armed officers were to be deployed on public patrol as part of anti-terrorism plans.
Russell Square was also the site of a coordinated Islamist attack on July 7, 2005. A bomb was detonated on a train traveling between the King’s Cross St. Pancras and Russell Square underground stations, resulting in the deaths of 26 people.