The air defence systems in United Arab Emirates are responding to missile threats, the country's defence ministry says.The UAE defence ministry said sounds heard across the country "are the result of ongoing engaging operations of missiles and UAV's".Security alerts were sent out to mobile phones, a witness told Reuters.It comes as neighbouring Bahrain sounded air raid sirens after the United States struck Iran following an attack in the Hormuz strait.Bahrain's interior ministry urged citizens and residents to remain calm and head to the nearest safe place.More to come- AFP