Sergei Roldugin
Cellist Sergei Roldugin (left) has been a friend of Vladimir Putin's for decades Reuters

The Russian President Vladimir Putin has lashed out at allegations he is tied to a $2bn (£1.4bn) offshore fortune, calling a massive leak from the Panamanian law firm Mossack Fonseca an effort to weaken the Russian State.

Putin, like dozens of world leaders, has been implicated in the so-called Panama Papers leak, the disclosure of more than 40 years' worth of documents detailing payments and transactions into shell companies in offshore tax havens.

Leaked documents from Mossack Fonseca reveal how one of Putin's childhood friends, cellist and businessman Sergei Roldugin, reportedly controlled, directly or indirectly, a group of companies that would make transactions with large state-owned Russian companies.

The companies would apparently take donations from Russian businessmen or make loans from the Cyprus-based RCB Bank, which has a large stake controlled by the Russian state-owned VTB Bank.

Speaking in St Petersburg on 7 April, Putin, said even though his name did not figure in any of the documents leaked from a Panamanian law firm, Western media pushed the claims of his involvement in offshore businesses.

The Press Association reported the Russia leader described the allegations as part of the US-led disinformation campaign waged against Russia in order to weaken its government.

Putin addressed the issue of his involvement with Roldugin. He said the musician's holding of such vast offshore sums was not an indication of any wrongdoing. He said he was proud of his friend, adding that the musician spent his personal money to advance cultural projects in Russia.

"Our opponents are above all concerned by the unity and consolidation of the Russian nation. They are attempting to rock us from within, to make us more pliant," said Putin, according to Reuters, in his first public comments on the leaks.

"There is a certain friend of the president of Russia, he did such and such a thing, and there is probably a corruption element there," Putin said, describing the allegations."But there isn't any [element of corruption]."

Mossack Fonseca has denied any wrongdoing. "We are a company who after almost 40 years has never been formally accused of anything. We are dedicated to doing legal structures which we then sell to intermediaries like banks or lawyers or accountants and they manage it from there and we do not have any control over that. We are not responsible for how they manage those structures however they may want to do them," the firm said in a statement.