Protesters are seen during a protest against the Land Forces International Land Defense Exposition at the Melbourne Convention and Entertainment Centre in Melbourne, Australia, on Wednesday. Photo by Con Chronis/EPA-EFE
Sept. 11 (UPI) -- Police arrested 42 people at the Land Forces Defense Expo in Melbourne on Wednesday in the largest protest the Australian city has seen in more than two decades, authorities said.
Officials said 27 police officers were injured during the demonstration that grew more violent throughout the day as about 1,000 law enforcement personnel from Victoria and New South Wales gathered at the Melbourne Convention and Exhibition Center for the expo.
An estimated 1,500 protesters traveled to Melbourne to protest the event. Some blamed the demonstrators for throwing what was believed to be human feces and horse manure, rocks and other objects, and balloons with unknown liquids at officers.
Authorities said that of those arrested, 22 had been charged and released on bail, 10 others had been fined and another 10 were expected to be charged with a summons at a later date.
"If people come into protest -- I would urge them not to -- but if they do and they do so peacefully, happy days," Victoria Police Chief Commissioner Shane Patton said, according to the Australian Broadcasting Corp. "But if they break the law, we will hold them to account."
Patton said the protesting groups made no effort to communicate with police before Wednesday.
"We do try and engage with all issue-motivated groups, so we can set standards and agree to conduct," he said. "That wasn't the case leading into this and we've seen how it unfolded."
Victoria Treasurer Tim Pallis said earlier in the week the police operation with the extra security could cost up to $10 million.