The Democratic Ulster Party's Paul Givan described the attack as despicable. He said protests should be stopped if they could not be peaceful.
It is vital that those who continue to have protests, if they cannot guarantee that there will be no violence; that there will be no blocking of roads and no disruption to people's way of life, that they do not go out onto the streets and they should desist from that activity.
More top news
The boy was found unconscious and in cardiac arrest and was rushed to hospital where he died.
The victim, who was wearing her uniform at the time, was found knocking on doors nearly four hours after she was abducted.
There will be gales across Scotland and northern England this morning, but these will gradually ease through the afternoon.