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PARIS — A knife-wielding man shot dead by Paris police on Thursday was carrying paper with an ISIS flag on it as well as a claim of responsibility, according to the Paris prosecutor.

The incident came as France marked the one-year anniversary of the deadly Charlie Hebdo terror attacks.

The prosecutor's office said a terrorism investigation has been opened into the incident, which took place outside the Goutte d'Or police station in the 18th arrondissement.

The suspect was carrying a butcher's knife and shouted "Allahu akbar" — or "God is greatest" — before he was shot dead by police, according to a statement from the prosecutor's office.

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It said a piece of paper with the ISIS flag and a claim handwritten in Arabic were found on the suspect, along with a cellphone. The suspect's identity has not yet been confirmed, the statement added.

What initially appeared to be an explosive device on the suspect was ultimately deemed "fake," Ministry of the Interior spokesman Pierre-Henry Brandet earlier told NBC News.

The neighborhood where the attempted attack occurred was essentially locked down for hours, with armed police securing the area and numerous emergency services vehicles on site.

France's interior minister, Bernard Cazeneuve, paid a visit to the scene where he praised the courage of police and expressed his support for their front-line work.

News of the shooting came shortly after French President Francois Hollande told police forces that a "terrorist threat" remained in an address marking the grim anniversary.

The office of Charlie Hebdo, a satirical magazine, was the first target in a multi-day terror spree which began on Jan. 7, 2015. The attacks left 20 people dead, including three terrorists.

Less than a year later, Islamist extremists laid siege to Paris and killed 130 people across the city.

France has been under a state of emergency since those Nov. 13 attacks.