Australian riot police fired rubber bullets to dispel a crowd of people demonstrating against Melbourne's coronavirus lockdown.
More than 200 people were arrested after projectiles thrown by demonstrators injured two officers on Wednesday.
Police were pelted with golf balls, batteries, and bottles during what was the third consecutive day of demonstrations against the COVID restrictions.
The protests defied stay-at-home orders following a two-week closure of building sites in an effort to rein in infections, which have risen in the state of Victoria.
Vaccines have been made mandatory for construction workers and authorities closed construction sites from Tuesday, citing non-compliance with coronavirus rules.
Police are preparing to face more demonstrations in the coming days, deputy commissioner Ross Guenther said, before adding that the motives of some protesters appeared unclear.
"There weren't as many tradies (tradespeople) involved...there are other small breakaway groups that see benefit in hijacking these things," he said.
"We've got plenty of resources. We will vary our tactics tomorrow, if that is what we need to do, but of course, my message is: 'Don't come into the city.'"
Protesters face fines of A$5,000 (£2,700) for breaching COVID rules, Mr Guenther added.
Authorities and union officials had warned that extremist and far-right groups have also joined the protests.
"There were some people there who you would say were from the building industry," Victoria state premier Daniel Andrews said.
"There were others who were not. They are not there to protest, they are there for a fight, pretend to be protesting."
Protesters roamed the streets and around 300 gathered at a city landmark, though most avoided clashes with police, who had been brought into the area after more than 2,000 demonstrators damaged property and injured three officers on Tuesday.
Australia has locked down its largest cities, Sydney and Melbourne, as well as the capital, Canberra, for weeks in response to an outbreak of the Delta variant.
It is the sixth lockdown for Victoria's capital, Melbourne - the most of any Australian city.