Zurich: Four bankers -- three Russian-born and one Swiss -- on Thursday (local time) were charged with breaking Swiss anti-money-laundering law of having assisted a long time ally of Russian President Vladimir Putin, reported The Wall Street Journal (WSJ).

A Zurich court found four Gazprombank bankers guilty of not conducting proper checks when opening accounts linked to a close friend of Russian President Vladimir Putin years ago.

They were found guilty of failing to exercise due diligence over accounts linked to a prominent friend of the Russian president. All four worked for Gazprombank, the main channel of Russian gas and oil payments.

The accounts in question were opened in the spring of 2014 at Gazprombank's Swiss unit by companies owned by Sergei Roldugin, a concert cellist close to Putin, reported WSJ.

The Zurich prosecutors alleged that Roldugin's ownership of the companies and the dividend payments he received through the accounts were implausible given his background as a musician.

The four men face fines ranging from 48,000 Swiss francs to 540,000 francs, the equivalent of USD 52,000 and USD 590,000, respectively, and two years of probation, the court said. If they behave in that period, they don't have to pay the fines, reported WSJ.

However, all four of them denied the charges. A lawyer representing one of the men said the four will appeal the verdict.

Switzerland for decades provided shelter for the money and assets of Russian oligarchs. The trial has been seen as a test of the country's will to keep out illicit money, after stepping up anti-money-laundering efforts in recent years, reported WSJ.

The country shed its historic neutrality last year when it adopted European Union sanctions against Russia over Ukraine's invasion.

Swiss banks said they have frozen tens of billions of dollars in sanctioned client assets since then, reported WSJ.

Gazprombank, created to serve the financial needs of Russia's Gazprom, bought its Swiss banking unit in 2009 from another Russian bank. It mainly served Russian and Swiss companies and commodities traders, according to Gazprombank Switzerland's financial reports.

In 2018, Swiss financial regulator Finma said there were serious shortcomings in Gazprombank Switzerland's anti-money-laundering processes and temporarily banned it from taking on new private clients. Last year, the bank said it was shutting down its operations, reported WSJ.

Gazprombank Switzerland's parent bank, based in Moscow, has been largely spared of sanctions by the US and the EU so that Western companies could continue to make gas and oil payments to Russia.