Roundup: American woman killed in central London's attack

London Metropolitan Police announced Thursday that a Norwegian national of Somali origin has been arrested on suspicion of murdering an American woman and injuring five others, in an attack on Wednesday night in central London.

Speaking outside Scotland Yard headquarters, Metropolitan police assistant commissioner Mark Rowley said there was no evidence that the 19-year-old suspect had been radicalized or was motivated by terrorism, and reasserted the view that "mental health issues" played a significant role.

The suspect emigrated from Norway to Britain in 2002, at the age of five, according to the Norwegian embassy.

The Metropolitan Police said they received numerous calls starting at 10:30 p.m. local time (2130 GMT) describing a "man attacking people with a knife" between Russell Square, Montague Street, Bloomsbury Square and Great Russell Street.

The man was arrested at the scene after police stunned him with a Taser following the attack, near the Imperial Hotel and the British Museum. The suspect was taken to a south London police station after receiving treatment in hospital.

"While the investigation is not yet complete, all of the work we have done so far increasingly points to this tragic incident as having been triggered by mental health issues," Rowley said. "Indeed at this time we believe it was a spontaneous attack and the victims were selected at random," he added.

Rowley said the woman who was murdered was American national, while those injured are Australian, American, Israeli and Briton. He said the police have spoken to relevant embassies and will do everything possible to support them.

U.S. ambassador to Britain Matthew Barzun expressed condolences on his twitter account: "Heartbreaking news that a U.S. citizen was killed in #RussellSquare attack. My prayers are with all the victims and their loved ones."

The mayor of London, Sadiq Khan, called for the public to remain calm and vigilant. The police were doing an incredibly difficult job, the mayor said, adding that the safety of Londoners was his "number one priority".

The attack came on the same day the Metropolitan Police announced it was to increase the number of armed patrols in London as part of anti-terrorism plans.

The London Metropolitan Police chief Sir Bernard Hogan-Howe on Sunday warned a terror attack in Britain was a case of "when, not if".

The London incident followed a series of attacks in other European countries, although Britain had been relatively quite. Endit