Greek riots, day #5: Crackdown on union strike marches

Syntrivani Sq., 20' ago. I've no idea what this is all about.
20:15 (GMT+2) It appears that the dean of Aristotle U. is negotiating with rioters. The atmosphere is electrified, riot squads have been deployed, plainclothes cops are spread out throughout the crowd, shopkeepers & car owners were evacuating Ethnikis Amynis avenue.
20:44 (GMT+2) The situation has been static for the past half hour. Two mobs standing 200m apart north of Syntrivani, small clusters of people dotting the street, while the rest of it is deserted. Looks like OK Corral before the battle
21:14 (GMT+2) The standoff continues, although it looks like the tension is slowly bleeding away & the mobs are progressively thinning out. That's a probably a good thing, I suppose
21:40 (GMT+2) From a distance, the situation seems to have been defused; a crowd is milling about outside the U. main gate, with a lesser one loitering around Syntrivani (probably onlookers & assorted security), but no tension is apparent & the smoke from burning litter bins has died down.