Police say that 19 people have been killed and another 50 injured after an explosion at the Manchester Arena in northern England, where U.S. pop star Ariana Grande was giving a concert. $ \& O# [2 J! N2 ^; B7 T9 X* q 4 ~, X& G; `4 J5 X1 w: ^9 wThey say they are treating it as a "terrorist incident" as they investigate.