Protesters have punched horses and pelted officers with rocks, cans of baked beans, horse manure and acid, says the chief commissioner. Meanwhile, police have been accused of using excessive force.
In short:
There have been clashes between police and a large group of protesters outside the Melbourne Convention and Exhibition Centre where a major defence and weapons expo is being held.
Hundreds of officers have been called in for what Victoria Police say is their biggest operation since the S11 protests outside the World Economic Forum in Melbourne 24 years ago.
What's next?
Police and protesters are expected to remain on scene in large numbers throughout the conference.
Rubber bullets are especially concerning. Many of us saw the damage they did to journalists and protestors who were shot with them in the US protests by police a few years ago.