Berlin: An international coalition of media outlets on Sunday published what it said was an extensive investigation into the offshore financial dealings of the rich and famous, based on a vast trove of documents provided by an anonymous source.

The International Consortium of Investigative Journalism, a nonprofit organization based in Washington, said the cache of 11.5 million records detailed the offshore holdings of a dozen current and former world leaders, as well as businessmen, criminals, celebrities and sports stars .

ICIJ has exposed the secret offshore dealings of aides to Russian president Vladimir Putin, world leaders and celebrities including Barcelona forward Lionel Messi.

According to AFP, Among the main claims of the ICIJ investigations:-- Close associates of Putin, who is not himself named in the documents, "secretly shuffled as much as USD2 billion through banks and shadow companies," the ICIJ said.

-- The files identified offshore companies linked to the family of Chinese President Xi Jinping, who has led a tough anti-corruption campaign in his country, the ICIJ said.

-- In Iceland, the files allegedly show Prime Minister Sigmundur David Gunnlaugsson and his wife secretly owned an offshore firm holding millions of dollars in Icelandic bank bonds during the country's financial crisis.

-- The law firm of a member of FIFA's ethics committee, Juan Pedro Damiani, had business ties with three men indicted in the FIFA scandal: former FIFA vice president Eugenio Figueredo, as well as Hugo Jinkis and his son Mariano who were accused of paying bribes to win soccer broadcast rights in Latin America.

-- Argentine football great Messi and his father owned a Panama company, Mega Star Enterprises Inc., a shell company that had previously not come up in Spanish investigations into the father and son's tax affairs.

Also in the world of football, Francetvinfo named UEFA president Michel Platini as the beneficiary of a Panama-based tax company, adding however that no illegal activity was alleged.

The ICIJ said the documents included emails, financial spreadsheets, passports and corporate records detailing how powerful figures used banks, law firms and offshore shell companies to hide their assets. The data spanned a time frame of nearly 40 years, from 1977 through the end of 2015, it said.

"It allows a never-before-seen view inside the offshore world — providing a day-to-day, decade-by-decade look at how dark money flows through the global financial system, breeding crime and stripping national treasuries of tax revenues," the ICIJ said.

According to the media group's website, global banks including HSBC, UBS, Credit Suisse, Deutsche Bank and others have worked with Mossack Fonseca to create offshore accounts.

"The allegations are historical, in some cases dating back 20 years, predating our significant, well-publicized reforms implemented over the last few years," HSBC spokesman Rob Sherman said in an emailed response to an AP request for comment.

"We work closely with the authorities to fight financial crime and implement sanctions," he said.

UBS, Credit Suisse and Deutsche Bank did not immediately respond to a request for comment.