A Moscow court has confirmed that a prominent Russian opposition figure has filed a suit which accuses President Vladimir Putin of breaking the nation's anti-corruption law.

The Tverskoy Court told The Associated Press on Friday that papers were filed by Kremlin critic Alexei Navalny. He accuses Putin of failing to declare a conflict of interest regarding a low-interest, $1.75 billion loan granted to a company where a man described as Putin's son-in-law is a shareholder.

Navalny wrote in a Thursday blog post that the petrochemical production company Sibur, where Kirill Shamalov is a member of the board of directors, was charged an unusually low 2 percent interest rate on the loan from Russia's National Wealth Fund.

The court did not respond to repeated requests about the status of the suit.