The chairman of the board of Russia’s largest private oil company Lukoil has died, with the country’s news agencies citing sources saying he had fallen from a hospital window in what may have been a suicide.

A Lukoil statement said Ravil Maganov had “passed away after a severe illness” but did not give further details.

Russian news reports said his body was found in the grounds of the Central Clinical Hospital in Moscow, where Russia’s political and business elite are often treated. He appeared to have fallen from a sixth-storey window, the reports said.

State news agency Tass cited an unnamed law enforcement source as saying Mr Maganov had taken his own life and that he had been admitted to the hospital after a heart attack. The news site RBK also said police were investigating the possibility of suicide.

Lukoil was one of a few Russian companies to publicly call for an end to the country’s military operation in Ukraine, pressing in March for the “immediate cessation of the armed conflict”.

A former top manager of Lukoil was found dead in the basement of a residence in a Moscow suburb in May.

Russian news reports said the house belonged to a self-styled shaman who practiced purification rights.

Investigators said the preliminary of cause of death was determined to be heart failure.