It says Ghetto - so its probably Nazis clearing a Jewish ghetto in Poland in WW2 - maybe the fighters had some kind of uniform.
I hadn't bothered to enlarge the photo the first time, and didn't even notice the Ghetto caption in the upper left. Something else I now see which had escaped my attention earlier is that two of the Nazis are helping the hanging along by pushing down on the victim from above and pulling him down from below. You can clearly see the effort being exerted in the face of the guy on the far right.
"...he shows an immediate ease with the handgun that I imagine is second nature to all letter carriers."
Stephan Jaramillo, Going Postal