Officials have confirmed that the man who was beheaded in broad daylight outside a London military barracks Wednesday was a soldier, although his identity has yet to be released. Prime Minister David Cameron—who called the incident “sickening” on Twitter Thursday—held a meeting with the government’s emergency response committee, Cobra. While the investigation continues, British soldiers have been warned not to wear their uniforms outside. After leaving the Cobra meeting, London Mayor Boris Johnson cautioned against classifying the two attackers—who have both been arrested— as Islamic extremists. “It is completely wrong to blame this killing on the religion of Islam,” he said. “What we need now… is justice."