Defense systems will need to be invented rather quickly for this stuff and it will need to be electronic.
Drone technology happens to be truly scary. What limits it is the need for trained manpower. Yet it is also no trick to order out a swarm of micro drones and to allow short range hunter killer independence similar to a swarm of angry bees.
It can be countered by rapid firing laser weapons which are also becoming operational..
What it is doing is making the soldier even more tech dependent.