UK Home Secretary Amber Rudd on Tuesday (23 May) called the explosion at Manchester Arena in northern England that killed 19 people as a barbaric attack. She called on the Mancunians to remain alert but not alarmed. The attack appears to be the most deadly attack Britain has witnessed in a decade. British Prime Minister Theresa May, who called the incident an appalling terrorist attack, is set to chair a Cobra emergency meeting on Tuesday as she suspended her campaign activities.