Neighborhood kids disturbing my dog

We moved to a South Auckland suburb in August and never imagined that a bunch of kids would slowly become our worst nightmare.

We have a fully fenced property and keep our Pitbull cross pet in the backyard when we are not home. There is a park across our property where kids from the neighborhood play every evening. Off late, the kids have been mean to our dog. I caught them throwing stones at our fence which obviously agitated our dog causing him to bark and just be on guard all the time when they are around. One of them even threw a metal rod inside our property. I am not sure if it was aimed at our dog.

We have cameras installed in the front and backyard and saw one of the kids last week sticking their face over the fence and my dog was just feet away from her. If he wanted to jump and get her, he could.

Yesterday I came back home early from work and saw the kids standing by the fence, mimicking my dog barking, making my dog bark endlessly. He almost slid his paws under the fence, trying to get them.

I have never seen the parents of these kids around. If my dog gets to any of them, obviously he will be deemed at fault and put down. It's so unfair.

How do we deal with this?

Looking for a bit of advice on what can be done in this situation we are in.