Shortly before Greek PM Tsipras spoke at today's huge "No" rally on Syntagma square, scuffles in the crowds of protesters broke out and police have resorted to stun grenades and tear gas.

As Reuters reported, "Greek police threw stun grenades and scuffled with protesters in central Athens on Friday, as a rally got under way in support of a 'No' vote in a Sunday referendum on whether to endorse an aid deal with creditors. The scuffles involved a few dozen people, many dressed in black and wearing helmets but quickly appeared to calm."

Luckily, the violence was scattered and promptly dissipated.