In London, police are investigating Saturday’s knife attack on a man at an East London metro station as a terrorist attack. The police say they were told the attacker shouted, “This is for Syria.” Richard Walton, counterterrorism police chief, said the attacker’s motives are still unknown.

Richard Walton: “It’s too early to be absolutely certain about the motives for this attack. Obviously, the Counter Terrorism Command is investigating it. We’ve got a number of lines of inquiry, and we’re pursuing this investigation with some speed to determine what happened, how it happened, and particularly the motive that lies behind the attack.”