Story highlights CBC says it obtained a top secret NSA document from Edward Snowden

It says the U.S. conducted surveillance during the G8, G20 summits in Toronto

This was "closely coordinated with the Canadian partner," the NSA says, reports CBC

U.S. agencies haven't responded to comment on this report

The United States -- in partnership with its ally Canada -- spied during a pair of major 2010 summits of world leaders in Toronto, CBC reported, citing top secret documents obtained from whistleblower Edward Snowden.

Both the G8 and G20 summits were held in June 2010 in Canada's most populated city. And both times, America's National Security Agency conducted widespread surveillance that was "closely coordinated with the Canadian partner," according to CBC's account of a briefing note from the U.S. spy agency.

The multi-day spying operation focused at making sure meeting sites were safe, protecting against terrorist threats and "providing support to policymakers," a NSA briefing document states, according to the Canadian news outlet.

The National Security Agency and the office of Director of National Intelligence, President Barack Obama's top intelligence adviser, did not respond Thursday to CNN requests for comment on the CBC report

Ottawa's Communications Security Establishment Canada, or CSEC, did not comment to the CBC, according to that news outlet.

When similar reports have surfaced in the past. U.S. government officials have pointed to the Obama-ordered review of America's intelligence gathering -- which gained steam after reports that German Chancellor Angela Merkel had been spied on -- but refused to comment on specific claims.

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But they also have not backed away from the idea that the U.S. spies, just like other nations do.

"As we have made clear, ... the United States gathers foreign intelligence of the type gathered by all nations," said NSA spokeswoman Caitlin Haden in October, when the Merkel reports stirred tensions between traditional allies in Germany and the United States.

The new CBC reporting does not specify which world leaders, if any, were targeted during the G8 and G20 summits, or what specific information may have been obtained.

Nor does the Canadian news outlet's account of the NSA documents spell out what role, if any, the CSEC had in it. If that Canadian agency had been complicit in snooping on anyone -- be they Canadians or foreign nationals -- without a warrant, it could violate that North American nation's laws, the CBC reports.

G8 summits are meetings of world leaders from the Britain, Canada, France, Germany, Japan, Russia, the European Union and the United States. G20 summits incorporate a larger group, traditionally taking place once or twice each year.

During these meetings, leaders traditionally discuss a wide range of important and sometimes hot-button issues. At the end of 2010's G8 summit in Toronto , for example, the group issued a final statement focusing on recovery from a global economic crisis while also criticizing Iran and North Korea.

The fact that Snowden is linked to the CBC's report isn't a big surprise.

The now 30-year-old worked as an information technology contractor for the U.S. government. He collected information on his native country's spy programs, then exposed them to media outlets such as the Guardian and the Washington Post.

Some of the reported leaks -- like that the National Security Agency mined phone and Internet metadata from thousands of people inside and outside of the United States -- put the Obama administration on the defensive, trying to justify its spying programs while assuring Americans of their privacy. Others, like the claims that Merkel was spied on for years, forced Washington to do damage control with leaders of countries overseas.

U.S. authorities have charged Snowden with espionage and theft of government property. But they haven't arrested him: Instead, he is in Russia, which on August 1 granted him asylum for one year.

This isn't the first time that documents from Snowden have been linked to G20 spying.