A French news magazine claims that the United States hacked the computers of France's political leaders prior to the country's presidential elections last May.

According to the publication, L'Expresse, the attackers were able to access computers belonging to an adviser of former French president Nicolas Sarkozy, who was defeated in the election by Francois Hollande.

The publication quoted an anonymous source who reportedly said the targeted information involved France's relations in the Middle East and the ways in which the potential outcomes of the French election might impact those relations.

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The attackers reportedly identified individuals working at the presidential palace through Facebook and then used those connections to launch a phishing attack that eventually resulted in the theft of network login credentials. Once access had been secured, the report claims that the attackers then installed Flame malware and were eventually able to penetrate the computer of one of Sarkozy's top aides.

The Flame virus has been widely covered in the news, and it is able to gather a wide variety of information, including keystrokes, screen shots, audio and video of infected devices. It has allegedly been used by the United States and Israel against a number of countries in the Middle East.

The magazine does not provide details of how the investigation pointed to U.S. sources, and the French government did not comment. While U.S. Secretary of Homeland Security Janet Napolitano would neither confirm nor deny the allegation, the United States Embassy in Paris denied any wrongdoing.

"We categorically refute allegations of unidentified sources, published in an article in the Express, that the government of the United States of America has participated in a cyber attack against the French government," said Embassy spokesperson Mitchell Moss, in a prepared statement. "France is one of our best allies. Our cooperation is remarkable in the areas of intelligence, law enforcement and cyber defense. It has never been so good and remains essential to achieve our common fight against extremist threat."

PUBLISHED NOV. 21, 2012