The environmental activist movement in Canada has been targeted by the Canadian government as a threat to national security, according to documents recently released under a freedom of information law, the Guardian reports.

According to Jeffrey Monaghan of the Surveillance Studies Center at Queen's University in Kingston, Ontario, who obtained the previously unreleased government documents, security and police forces have been closely surveilling peaceful environmental activists, including many who are planning to attend the Washington DC Keystone XL Pipeline protest on Sunday.

"Any Canadians going to protest the Keystone XL pipeline in Washington DC on Sunday had better take precautions," Monaghan told the Guardian.

"It's the new normal now for Canada's security agencies to watch the activities of environmental organizations," he added.

"Security and police agencies have been increasingly conflating terrorism and extremism with peaceful citizens exercising their democratic rights to organize petitions, protest and question government policies," Steven Leahy reports at the Guardian.

Canada's national police force and the Canadian Security Intelligence Service (CSIS) say activists engage in "forms of attack" through acts of civil disobedience such as blocking access to roads or buildings.

Monaghan added that in particular, protests in opposition to Canada's oil and gas industry are viewed as threats by Canadian authorities.

Read more at the Guardian here.