Note how all this look like a professional organisation, including air-defense:
Since the rebels don't have air crafts, it means they are prepared for attacks by the Russian air force. Of course it can also be used against other targets.
Link to Wikipedia on the ZSU.
This is a another screenshot:
Note how the bank in the middle starts at this point.
On the road North of Lugansk, this is that location:
On a larger scale:
The Russian border is only 30 kms away.