Vancouver police department's gang crime unit is defending the use of surveillance cameras towering over an East Vancouver neighbourhood, saying it's one of many approaches it is taking to prevent violence.

"We have been very successful at reducing gun and gang violence in the city," said Const. Brian Montague.

"This is not the first time we have put this unit out, and the cameras are only one of a number of proactive approaches we take."

The four cameras, which are mounted on a tall pole on top of a small trailer, have been deployed near East 22nd Avenue and Kaslo Street in Vancouver.

"Those living in the immediate area are informed that the cameras are there and why," said Montague.

Mixed reaction recorded

Despite the notice, some expressed surprise when the camera pole appeared.

Twenty-year resident Mona Robertson said she watched police erect it, and was shocked when she realized what it was for, leaving her with a lot of questions.

"What does this mean? What about my privacy. What about my daughter who has to walk to school in that area ... I am still trying to get my head wrapped around this," she said.

Robertson said she was aware there were a "few shootings" but did not realize it was "bad" enough to warrant a security camera.

"At what point does it invade my privacy ... and what are my rights?"

The mother of three said she did not find the camera comforting, it only raised her fears about family safety.

Social media takes notice

The gang crime unit tweeted out that they had erected the towering cameras on Tuesday, eliciting a mix of reactions on social media.

A group called Cannabis Oil Corp tweeted, "This is a huge invasion of my privacy on the premise of gang violence? what gang violence?"

"Starts with mobile in problem areas to full damn Orwell and UK once complacency sets in and the Beta test is complete." Tweeted Rob E, @bobbyboucher604, who changed his Twitter image to a photo of the cameras.

Among those who applauded the move were Debbie Fleming, who tweeted, "Thank you for all you do! Appreciate it."

Used around the world

Former B.C. solicitor general and former Vancouver police superintendent Kash Heed said police did their research before making the decision to put the cameras into a neighbourhood.

"This type of technique is used world-wide to prevent various types of crimes from occurring, whether it's gang violence or some other kind of public safety issues. [There's been] some success and some not as successful.

"It's something that police have in their toolbox to use and I think it's appropriate when we have an issue to ensure the public remains as safe as the police can make them."

Surveillance camera use has also been the subject of criticism by those who are concerned about privacy in public spaces.

Police argue that the impact on privacy is minimal because just having them there helps discourage criminal gatherings and activity.

Abbotsford Police often have two or three of the conspicuous units installed at any one time.

"We don't gather a lot of [intelligence] from the cameras. They tend to work more successfully in terms of suppressing and dissuading people from re-engaging in those types of incidents," said Abbotsford Constable Ian MacDonald.

The footage is kept and archived in case it becomes important during an investigation.