A man has been arrested on suspicion of murder after a US citizen was killed and five other people were injured in a knife attack in central London.
Police described the attack in Russell Square on Wednesday night as “random”.
The woman who died was thought to be in her 60s. The injured people were from Britain, America, Israel and Australia.
A 19-year-old Norwegian national of Somali origin has been arrested but police said there was no evidence of radicalisation.
Speaking at a press conference, the Met’s assistant commissioner for specialist operations, Mark Rowley, said the police investigation suggested the attack was “triggered by mental health issues”.
He said police believed it was a “spontaneous attack” and that the victims were selected at random.
Mr Rowley had earlier said the force was considering terrorism as “one line of inquiry for us to explore”.
Asked why he had said this, Mr Rowley said it was necessary to “consider all of the possibilities” following recent terror attacks across Europe.
The man was arrested after a Taser was discharged by an officer.
Scotland Yard said two other women and three men received various injuries in the attack, which happened near the Imperial Hotel.
Two from the group remain in hospital while the other three people have since been discharged, the force added.
After receiving treatment in hospital the arrested man, who was detained in Bedford Place, is now in police custody in a south London police station.
Mr Rowley earlier said the force’s homicide command was leading the investigation into the attack, with support from the counter-terrorism unit