Former NSA whistleblower Edward Snowden says Montreal's chief of police should resign, following the revelation that journalists were placed under police surveillance to determine possible media leaks in the department.

"This… is a radical attack on the operations of the free press," Snowden told a packed auditorium at McGill University. Snowden appeared via video link from Moscow, where he remains in exile after leaking classified NSA documents back in 2013.

Snowden had harsh words for police as well as local and provincial officials in Quebec, as he addressed the reports of surveillance on journalists. In particular, he addressed a report that Montreal's special investigations unit obtained 24 search warrants for La Presse columnist Patrick Lagace's iPhone as part of an internal probe which ultimately led to five arrests and two officers charged.

In his remarks Wednesday, Snowden called for Montreal police chief Philippe Pichet to resign, and questioned why Montreal Mayor Denis Coderre and Quebec Premier Philippe Couillard had not already asked the chief to do so.

He also pointed to the case as evidence that governments are developing "extraordinary capabilities to peer into all of our private lives," whereas members of the public "can know almost nothing about how they operate."

On Wednesday, various news outlets reported that six other journalists had been tracked by provincial police in 2013.