The Geneva prosecutor's office says Swiss authorities have frozen assets belonging to a Russian banker once close to President Vladimir Putin.

Spokesman Henri Della Casa of the Geneva prosecutor's office declined to specify the amount of assets frozen, but said the move came after Russia requested legal assistance from Switzerland in the case centering on Sergei Pugachev.

Following Swiss media reports over the weekend, Della Casa said Monday that Russia made the request in 2013, and documents were transferred in 2014. He declined to comment further.

Interpol in 2014 put Pugachev, a former Putin aide, on its most-wanted list. He is wanted by Russian authorities on charges of misappropriation or embezzlement.

The office of Benoit Le Bars, a Paris-based lawyer for Pugachev, said Le Bars was not available for comment.