The Met Police says the two victims were taken to hospital and their condition is unknown.
Objects could be seen on the ground at the scene next to the Lego store in Leicester SquareIn a post on, the Met Police said a man had been arrested and taken into custody, adding the force did not believe there were "any outstanding suspects".
A shop worker who helped stop the stabbing told the BBC he had heard "a scream", so he "jumped on the attacker... and kicked the knife away from him".Police officers remain at the scene, which is in one of the busiest tourist districts in the capital. He said a couple of other men also came over to help and held the man down for "four to five" minutes, adding he decided to take action because "I had no time, I just didn't think"."To do this to a kid, it's horrible."Shortly after the attack, several police officers were still at the scene next to the Lego store on Swiss Court, just off the square itself.
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