The Department of Foreign Affairs and Trade has confirmed two Australian tourists were among those injured in a stabbing attack in central London that left a 64-year-old US woman dead.

Armed police were called to the scene on Wednesday at 10:33pm (7:33am AEST) after reports that a man seen with a knife was injuring people at London’s Russell Square.

A 19-year-old Norwegian man of Somali origin was arrested minutes later, after being tasered by one officer, on suspicion of murder at the scene.

In a statement, a DFAT spokesperson said the Australians, a 40-year-old man and a 23-year-old woman, suffered non-life-threatening injuries.

London Metropolitan Police Assistant Commissioner Mark Rowley told reporters the Australians were two of five injured in the vicious attack along with US, British and Israeli nationals.

He said it appeared the incident was a “spontaneous attack and that the victims were selected at random.”

“We believe this was a spontaneous attack and that the victims were selected at random,” said Mr Rowley, who is Britain’s senior anti-terrorism officer.

“So far, we have found no evidence of radicalisation that would suggest that the man in our custody is in any way motivated by terrorism.”

Initially, Mr Rowley had said that terrorism was a line of inquiry.

– with other agencies