BELGRADE — The so-called Panama Papers project was organized by an Eastern Europe media network which is funded by the US Agency for International Development (USAID) and billionaire investor George Soros, WikiLeaks said Wednesday.

On Sunday, Germany’s Suddeutsche Zeitung published materials it claimed came from the Panamanian Mossack Fonseca company, exposing alleged involvement of a number of world leaders and their circles in tax havens schemes.

“#PanamaPapers Putin attack was produced by OCCRP [Organized Crime and Corruption Reporting Project] which targets Russia & former USSR and was funded by USAID & Soros,” WikiLeaks said on its Twitter account.

Mossack Fonseca responded by refusing to validate the information contained in the leaks and accused reporters of gaining unauthorized access to its proprietary documents. It warned that using unlawfully-obtained data was a crime that it would not hesitate to punish by legal means.