One American is dead and another injured after a Norwegian national went on a stabbing spree in central London Wednesday.

FOX's Simon Owen reports from London:

London jolted by this attack, which police initially said may have been terror-related, but as the day's gone on here they're now saying the violence appears to have been triggered by mental-health issues.

An American woman was killed and five other people injured in the rampage, which happened on a street in a busy part of Central London late yesterday evening.

A 19-year-old Norwegian man has been arrested. Police say he's of Somali origin. They say they've questioned him and searched properties and interviewed his family, and have found no evidence of a terrorist motive.

In London, Simon Owen, FOX News.

Follow Simon Owen on Twitter: @bigso