Germany seized the world's largest mega-yacht. It's worth $600 million and belongs to Russian oligarch Alisher Usmanov, a Forbes report says.

• Sanctions against Russia and its oligarchs have been implemented by several countries.
• A Russian billionaire had his yacht seized by German authorities on Wednesday, Forbes reported.

Germany seized Russian billionaire Alisher Usmanov's mega-yacht on Wednesday, according to Forbes, which cited multiple unnamed sources.

Usmanov's yacht, which has been docked in Hamburg, Germany, for months for a refitting, is the first to be seized since Russia's attack on Ukraine began on February 24.

Dilbar, a 512-foot yacht that weighs 15,917 tons, "is the largest motor yacht in the world by gross tonnage," according to Lürssen, the German ship's maker.

Usmanov bought the custom-built yacht for an estimated $600 million and it took 52 months to build, according to Forbes.

The US State Department was unable to confirm to Insider if the yacht was indeed seized. Usmanov and Germany's Federal Foreign Office did not immediately respond to Insider's request for comment.

Many countries, including the US and the European Union, have implemented sanctions — financial consequences applied by one party to another — against Russian banks, Russian oligarchs, and even Russian President Vladimir Putin, in an effort to end the country's full-scale invasion of Ukraine.

Usmanov's assets were frozen as part of sanctions levied by the European Union, according to the Guardian. After the European Union announced sanctions against Usmanov and other Russian oligarchs, he stepped down as President of the International Fencing Federation, one of his companies.

"I believe that such a decision is unfair, and the reasons employed to justify the sanctions are a set of false and defamatory allegations damaging my honor, dignity, and business reputation," Usmanov said in a statement on the company's website.

"I hereby suspend the exercise of my duties as the President of the International Fencing Federation effective immediately until justice is restored," he added.

The oligarch has historically supported Russian President Vladimir Putin, though he has not commented on the current attack on Ukraine.

"I am proud that I know Putin, and the fact that everybody does not like him is not Putin's problem," the Uzbekistan-born oligarch told Forbes in a 2010 interview.