The federal police are apparently moving into the areas of Oaxaca City that have been controlled by the protesters. They have small tanks and lots of riot troops.
Apparently people are putting their bodies in front of the tanks. calling it "human rugs" in front of the tanks.
This is according to the live APPO radio stream coming from the University radio station there, which has been operated by protestors for some weeks.

The names of all 4 dead from Friday: Emilio Alonso Fabi