South Australian police have defended a new security unit after public backlash against the presence of heavily armed officers on streets and at major events.
The rapid-response unit, dubbed the Security Response Section (SRS), comprises officers who have received advanced training to respond to terrorist situations, and carry semi-automatic weapons.
The section began patrolling public areas earlier this week, with police advising officers would be "highly visible" in areas including Adelaide Central Market, Rundle Mall, Adelaide Oval and the city's main railway station.
SA Police Commissioner Grant Stevens would not disclose whether the SRS would be deployed to patrol a Black Lives Matter Rally due to take place in Adelaide on Saturday.
"A decision will be made by the police commander as to whether SRS will be deployed to the Black Lives Matter protest tomorrow," he said.
"It's not the normal course for us to disclose our operational tactics.
"Being deployed into the central business district is something that I would expect them to be doing."
Police have previously said the SRS would provide "an extra layer of protection" at events where "large crowds gather".
But the unit has been met with criticism, with police forced to switch off comments on an Instagram post spruiking the SRS because "people were using abusive and offensive language".
"SA Police is now deploying officers armed with assault rifles … we don't want American gun culture here," a Twitter user wrote.
An online petition has been launched calling on SA Police and the State Government to "immediately and permanently disband" the SRS.
The petition's creator, Ripley Newbold, said he started it after he saw images of police officers holding assault rifles in Rundle Mall.
"I couldn't quite understand why we would need something like that," he said.
"I felt the justification SAPOL has given for their existence, it's really flimsy at best."
Natalie Wade, from the group Australian Lawyers for Human Rights, acknowledged the need to protect the public from terrorism, but also expressed concern.
"It's something we haven't seen a lot of in Australia," she said.
"It's perhaps something Australians have seen in the media in America and other countries around the world, but it's a foreign concept to the way Australia has been policed in the past."
Unit will tackle 'lone hostile actors'
The petition was signed by more than 3,500 people in its first 24 hours online, and has gained traction on social media platforms.
Mr Newbold said it was "disturbing" to think that the force would patrol the streets of Adelaide.
"The message they need to send is: 'we're here to protect the community', and the message that it sends is: 'I'm ready to shoot the second I feel threatened'," he said.
"That's not the type of policing I want in my community."
Police on Friday defended the unit, saying it would significantly bolster public safety.
"Security Response Section has been established to protect the community of South Australia," Commissioner Stevens said.
"They do that [by] being present at certified large gatherings where there is a risk of a lone hostile actor or a hostile vehicle incursion that could present a risk to that gathering."
On its website, SA Police said SRS officers "go through an intensive and specialised training program" in addition to their general police training.
"SRS officers are highly trained in the use of all their tactical options and in the safe handling and use of firearms," SA Police said.
"They are focused on prevention and response to terrorism-related incidents, domestic events of a violent nature and safely managing major events in South Australia."
