KYIV — Ukrainian anti-corruption investigators searched the home of Andriy Yermak, President Volodymyr Zelenskyy’s influential chief of staff, early Friday in a dramatic escalation of a widening $100 million graft scandal that has shaken Kyiv’s political leadership amid delicate U.S.-backed peace negotiations with Russia.

The National Anticorruption Bureau of Ukraine, or NABU, confirmed in a statement that investigators, together with the Specialized Anti-Corruption Prosecutor’s Office, were “conducting investigative actions” involving the president’s top aide. The agencies described the search as “authorized,” according to Reuters, and linked it to an ongoing probe into alleged kickbacks in the country’s state-run energy sector.

Yermak acknowledged the search shortly afterward, saying on Telegram that anti-corruption officials were “conducting procedural actions” at his residence and that he was offering full cooperation. “There are no obstacles for the investigators,” he said, adding that prosecutors had unrestricted access and that his lawyers were present and coordinating with law enforcement.

The raid marks the highest-level move yet in a corruption investigation that has already ensnared former senior officials and a suspended justice minister. Earlier this month, investigators revealed an alleged scheme in which current and former officials, along with business figures, received illicit benefits and laundered funds through Energoatom, Ukraine’s state atomic energy company, according to CNBC’s reporting.

The search also comes after weeks of mounting pressure on Zelenskyy to remove Yermak, a longtime confidant who helped steer the president’s 2019 campaign and has since become one of the most powerful figures in the government. Critics have argued for years that Yermak accumulated outsized influence and acted as an unofficial gatekeeper to the president — accusations amplified as the corruption scandal grew.

Although Yermak has not been named a suspect, opposition lawmakers and some members of Zelenskyy’s own party have called for his dismissal, portraying the moment as Ukraine’s most serious political crisis since Russia’s full-scale invasion began.

The timing of the search threatens to roil already-tense negotiations surrounding a U.S.-drafted peace initiative. Kyiv is under pressure from Washington to consider terms that align with certain Russian demands, according to Reuters, while the Ukrainian public remains vehemently opposed to territorial concessions. Yermak reiterated that stance in an interview with The Atlantic this week, saying “not a single sane person today would sign a document to give up territory.”

European Solidarity, a leading opposition party, criticized Yermak’s negotiating role in a Thursday statement and urged Zelenskyy to engage parliament in “an honest dialogue” about the government’s directives and red lines in ongoing talks.

Moscow, meanwhile, has seized on the corruption scandal to undermine Kyiv’s credibility. Russian President Vladimir Putin argued this week that a leaked 28-point U.S. peace plan “could be a basis for future agreements,” but insisted that Ukrainian troops must withdraw from eastern territory before Russia halts its offensive.

Putin has repeatedly accused Zelenskyy’s government of mismanaging resources and “sitting on golden pots,” rhetoric Kremlin officials have used for years to cast Ukraine’s leadership as self-interested — despite extensive corruption allegations leveled against Putin and his circle.

As Russian forces advance near Pokrovsk — a potential strategic gain after months of grinding warfare — analysts said Friday’s developments could alter Kyiv’s negotiating posture. Viktor Shlinchak of the Institute for World Politics described the moment as “a Black Friday” for Yermak, writing on Facebook that “it looks like we may soon have a different head of the negotiating team.”

Zelenskyy has not yet publicly commented on the search.