FRANKFURT, Germany (AP) - A leak of 11.5 million documents from a Panama-based law firm offers a glimpse into the shadowy world where the rich and powerful hide their money, raising sharp questions about the use of shell companies that obscure the identities of their true owners.
Leaders of the Group of 20 - representing about 80 percent of the global economy - have vowed to crack down on the practice, which is blamed for helping conceal money laundering, corruption and tax evasion.
By themselves, shell companies aren't illegal. Countries have tightened rules on using them - but not enough to satisfy anti-corruption activists.
News organizations working with the Washington-based International Consortium of Investigative Journalists have been processing the legal records from the Mossack Fonseca law firm that were first leaked to the Sueddeutsche Zeitung newspaper based in Munich, Germany.
In reports that began Sunday, they said the document dump that they dubbed the "Panama Papers" shows the hidden offshore assets of politicians, businesses and celebrities, including 12 current or former heads of state.
Among the countries with past or present political figures named in the reports are Iceland, Ukraine, Pakistan, Saudi Arabia, Russia and Argentina.
The law firm said in a statement it observed all laws and international standards covering corporate registrations.
Ramon Fonseca, a co-founder of Mossack Fonseca - one of the world's largest creators of shell companies - confirmed to Panama's Channel 2 that documents investigated by the ICIJ were authentic and had been obtained illegally by hackers.
But he said most people identified in the reports were not his firm's direct clients but were accounts set up by intermediaries.
One of the most prominent subjects of the report is Russian President Vladimir Putin, although his name does not appear in the documents. ICIJ said on its website that the documents show how complex offshore financial deals channeled as much as $2 billion to a network of people linked to Putin.
One focus was Sergei Roldugin, a professional cellist and childhood friend of Putin. Roldugen was listed as the owner of companies that obtained payments from other companies worth tens of millions of dollars, and of a stake in Bank Rossiya, described by the U.S. Treasury as "designated for providing material support to government officials."
"The evidence in the files suggests Roldugin is acting as a front man for a network of Putin loyalists - and perhaps for Putin himself," the consortium said. Roldugin was unavailable for comment Monday. A receptionist at the St. Petersburg House of Music, where he is artistic director, said he was not in.
Kremlin spokesman Dmitry Peskov claimed Putin was the "main target" of the investigation, which he suggested was the result of "Putinophobia" and aimed at smearing Russia in a parliamentary election year.
He suggested the ICIJ had ties to the U.S. government. The ICIJ is part of the nonprofit, non-partisan Center for Public Integrity, and neither takes U.S. government funding, said Peter Bale, CPI's chief executive.
Peskov said he would not go into the details of allegations that Putin's friends ran an offshore scheme, "mainly because there is nothing concrete and nothing new about Putin, and a lack of details."