Police in Australia's second largest city of Melbourne arrested more than 200 people after projectiles thrown by protesters injured two officers on Wednesday, the third consecutive day of demonstrations against COVID-19 curbs.
Golf balls, batteries and bottles were among the items thrown at police during the protests held in defiance of stay-at home orders after a two-week closure of building sites to rein in infections, which rose again in the state of Victoria.
Police are bracing for more demonstrations in the next few days, said deputy commissioner Ross Guenther, adding that the motives of some participants had seemed unclear.
"There weren't as many tradies involved...there are other small breakaway groups that see benefit in hijacking these things," Guenther told reporters.
"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.'"
Earlier, authorities and union officials had said extremist and far-right groups also joined the protests.
"There were some people there who you would say were from the building industry," state premier Daniel Andrews told reporters.
"There were others who were not ... they are not there to protest, they are there for a fight, pretend to be protesting."
Construction sites
The protests came after decisions by authorities to make vaccines mandatory for construction workers and shut construction sites from Tuesday, citing non-compliance with health rules.
Groups of protesters roamed the streets and about 300 gathered at a city landmark, but most avoided clashes with busloads of police after protests on Tuesday in which more than 2,000 demonstrators damaged property and injured three police.
Media complained after police asked the aviation authority to declare a no-fly zone above Melbourne, the capital of Victoria, in what Guenther called an effort to ensure that footage gave away no details of police tactics to protesters.
Later, the decision was modified to let TV helicopters film on condition of an hour's delay in broadcast, he added.
Television images showed a police group using capsicum spray and foam baton rounds to disperse hundreds of protesters at the Shrine of Remembrance, which honours war service. - Reuters