The chairman of Russia's Lukoil oil company, Ravil Maganov, has died after falling from a hospital window in Moscow.
The company confirmed his death but said only that Mr. Maganov, who is 67 years old, had passed away following a severe illness.
Russian media said he was being treated at Moscow's Central Clinical Hospital and died of his injuries.
Mr. Maganov is the latest in a number of high-profile business executives to die under mysterious circumstances.
Investigating authorities said they were working at the scene to establish how he died.
Russian News agency Tass quoted sources saying Mr. Maganov had fallen out of a sixth-floor window early Thursday morning, adding later that he had taken his own life.
Shortly after Russia invaded Ukraine, the Lukoil board called for the conflict to end as soon as possible, expressing sympathy for victims of the tragedy.