Former Russian President Boris Yeltsin’s son-in-law Valentin Yumashev has left his position as a Kremlin adviser, according to a Monday report by Reuters.

Reuters cited as many as two people close to the situation as saying Yumashev, described as a key element to Russian President Vladimir Putin’s rise to power, quit his role in April. He is the latest of several prominent Russian officials to resign since Putin launched his war on Ukraine.

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The news outlet noted Yumashev worked in an unpaid capacity and had only “limited influence on Putin’s decision-making,” but his name recognition, past influence and connection to Yeltsin make his resignation a high-profile loss to the Kremlin.

Lyudmila Telen, who works as first deputy executive director of the Boris Yeltsin Presidential Center—where Yumashev serves as a member of the board of trustees—reportedly said he left his position last month. She also indicated it was Yumashev’s own decision to leave.

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Another person said to be knowledgeable of the situation spoke with Reuters on the condition of anonymity. That source also said Yumashev stepped down from his role as a presidential adviser in April.

No explanation has been given for Yumashev’s departure, but his daughter posted an anti-war message with a Ukrainian flag on Instagram on February 24, the day when Moscow began attacks in Ukraine.

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Yumashev is married to Yeltsin’s younger daughter, Tatyana, and was once an aide to his since-deceased father-in-law. According to the BBC, Yumashev gave Putin his first job in the Kremlin in 1997. He was said to have later recommended to Yelstin that Putin become his successor.

Since Russia began its invasion of Ukraine, other top Russian officials have stepped down from their posts. One of the most powerful was Anatoly Chubais, a longtime government official who acted as Putin’s envoy to international organisations concerned about sustainable development.