Comment by pmontra

You might check how the Mongols managed to do it on a much vaster scale 800 years ago. For example https://en.wikipedia.org/wiki/Siege_of_Gurganj

The museum of the city has a paper with the order that every soldier would have to kill 400 people, by sword. Of course they were already captured but there were about 1 million people in that city. The city is still perfectly leveled after 800 years. Only a couple of buildings were left standing.

Mongols were very well coordinated. Iranian crowd control has had 45 years and several insurrections to train.