Sources tell CBC News the highest levels of the Canadian government have known for years that foreign countries have been trying to win influence over Canadian politicians and public servants.

Richard Fadden, director of the Canadian Security Intelligence Service, in an exclusive interview with the CBC. (CBC)That information comes a day after CSIS director Richard Fadden said he had never warned officials close to Prime Minister Stephen Harper that some provincial cabinet ministers may be under the sway of countries like China — even though he told the CBC earlier this week the agency was discussing the issue with the Privy Council Office.

Sources tell the CBC the PCO was well aware of those concerns, even if it hadn't been told the details of who was involved.

Public Safety Minister Vic Toews, the minister responsible for the Canadian Security Intelligence Service, Canada's spy agency, refused to discuss Fadden's bombshell allegations.

"I'm afraid I can't comment on any operational issues involving CSIS," Toews said Thursday.

In an exclusive interview with CBC News earlier this week, Fadden said Canada's spy agency suspects that some municipal politicians and cabinet ministers in two provinces are being swayed by their connections to foreign governments.

China was one of the countries Fadden mentioned.

The remarkable comments sparked outrage from some provincial politicians and have led some observers to call for Fadden to resign.

But senior intelligence sources say the highest levels of the Canadian government were "absolutely" aware of the issue.

"These problems are very well-known," one source said. "This information did not blindside the government."

Fadden 'not wrong': source

A source suggested the prime minister was personally aware of the issue of foreign agents trying to win influence over politicans and bureaucrats — even if he didn't know the details.

"The prime minister is strongly of a view that this is a problem," a source said.

The source said Harper has an appetite for intelligence beyond that of his predecessors. Intelligence briefers now routinely provide the prime minister with detailed written reports, in addition to their regular verbal briefings.

On Wednesday, the Prime Minister's Office denied it was warned by CSIS of any specific agents of influence in provincial cabinets. Fadden himself later issued a retraction on that key point.

But sources tell the CBC the issue was very likely "verbally briefed " to intelligence staff who work for the prime minister.

Fadden "had to swallow hard," a source said, "but he's not wrong."