What dog is aggressive to other dogs when I am close?

I have a 1.5 year old husky lab, he is neutered and is very friendly with other dogs and humans. However, he has been acting differently lately. He started becoming aggressive to other dogs whenever he was on-leash (showing teeth and growling). Also, when I bring him to a off leash dog park, he is very friendly until I get close to him and another dog. Like, if I'm getting close to him and another dog, he'll start growling at the other dog. Is he doing that because he is protective of me? How do I stop it ?

When your with another dog throw treats for him.

This is dangerous behavior, and I would discourage it before a accident happens. Imagine what problems it could cause if your dog was to be labeled dangerous - or if another dog was seriously injured, you could be charged the vet fees! Consult a dog trainer, they will know what is best for your dog. If worse comes to worse, muzzle the dog.

distraction, keep him on a training lead for the time being and work on the situation, try to get a friend who has a dog that may be able to help you recreate the situation. the i would suggest using the reward and non reward method, ie constantly giving treats and praise until there is behavior wish you find undesirable where then the show the dog the treat then take it away and walk the other way, most dogs find this incredibly confusing at first but stick in there a couple of times and your dog should learn to abandon the situation because he will see it as displeasing and disapointing