London's police force said they had received reports that shots had been fired on Oxford Street and in the nearby underground station, which they were responding to as if it might be terrorist-related.

"Police were called at 16:38 hrs ... to a number of reports of shots fired on Oxford Street and underground at Oxford Circus tube station," the Metropolitan Police said in a statement.

"Police have responded as if the incident is terrorist related. Armed and unarmed officers are on scene" the police added.

No casualties had been found so far, police said.