Paris, Apr 4 (AFP): A massive leak of 11.5 million tax documents has exposed the secret offshore dealings of aides to Russian president Vladimir Putin, world leaders and celebrities including Barcelona forward Lionel Messi.

An investigation into the documents by more than 100 media groups, described as one of the largest such probes in history, revealed the hidden offshore dealings in the assets of around 140 political figures -- including 12 current or former heads of states.

The vast stash of records was obtained from an anonymous source by German daily Sueddeutsche Zeitung and shared with media worldwide by the International Consortium of Investigative Journalists (ICIJ).

The investigation yielded 11.5 million documents from around 214,000 offshore entities, the ICIJ said. The leaked documents came from Mossack Fonseca, a Panama-based law firm with offices in more than 35 countries.

Though most of the alleged dealings are said by the ICIJ to be legal they are likely to have a serious political impact on many of those named.

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.

Platini's communications service said in a statement sent to AFP that "all of his accounts and assets are known to the tax authorities in Switzerland, where he has been a tax resident since 2007".