The U.S. National Security Agency carried out widespread surveillance during the 2010 G8 and G20 summits in Toronto, spying that was "closely co-ordinated" with Canada, CBC News reported Wednesday.
It is the latest in a series of revelations on NSA activities made possible by leaks from whistleblower Edward Snowden.
The briefing notes, stamped "Top Secret," show the U.S. turned its Ottawa embassy into a security command post during a six-day spying operation by the National Security Agency while U.S. President Barack Obama and 25 other foreign heads of government were on Canadian soil in June of 2010.
Notably, the secret NSA briefing document describes part of the U.S. eavesdropping agency's mandate at the Toronto summit as "providing support to policymakers."
Specific targets were not revealed.
A note within the documents states that the Toronto surveillance operations were "closely co-ordinated with the Canadian partner," the Communications Security Establishment Canada (CSEC), which CBC describes as having become "a formidable and sophisticated surveillance outlet."
Previous reporting on documents leaked by Snowden showed that the CSEC shared with the NSA information it obtained through "economic espionage" on oil and gas companies in Brazil.
In addition to the 2010 G20 summit being the target of spying, other documents leaked by Snowden revealed that the British government spied on delegates at the 2009 G20.