From the UK:
Police will have "no choice" but to shoot armed child

... "The volatility of these kids may make them pull the trigger. If they are challenged by an armed officer it is their inability to rationalise what is happening that will put the officer in a difficult position."

There has been a 20 per cent rise in the number of young people prosecuted for firearms offences over the past five years, with reports that children as young as eight are now using guns to solve disputes.

I don't know that I would be very happy with any law enforcement leadership that would phrase shooting children as "when" rather than an "if."

It is also noteworthy that for a society that has banned private ownership of firearms eight year old have no problem getting firearms.