The United States placed sanctions Friday on a Ukrainian business tycoon seen as the most powerful figure in the country outside of the government, signaling an aggressive new approach by the Biden administration to dealing with corruption in Ukraine.
The businessman, Ihor Kolomoisky, an oil and media magnate, was already under investigation in the United States on accusations of embezzlement and fraud, and of using the proceeds to buy commercial real estate in Cleveland, Ohio.
At home in Ukraine, he is one of the most prominent of the ultrawealthy class of post-Soviet oligarchs and has been both an ally and a political albatross for President Volodymyr Zelensky.
Ukrainian oligarchs exercise outsized influence in the country, controlling the news media and at times financing entire factions in Parliament at odds with American and European efforts to strengthen Ukraine’s pro-Western geopolitical orientation. They have done so even as they kept money in Western banks and investments and sent their children to live or study in Europe and the United States.
The sanctions were announced on Friday by the secretary of state, Antony J. Blinken, and bar Mr. Kolomoisky and members of his family from traveling to the United States because of “involvement in significant acts of corruption.”