The deputy head of Ukraine’s presidential office quit Tuesday, after Ukrainian President Volodymyr Zelenskyy pledged to launch a staff shake-up amid high-level corruption allegations during the war with Russia.

Kyrylo Tymoshenko asked to be relieved of his duties, according to an online copy of a decree signed by Zelenskyy and Tymoshenko’s own social media posts. Neither gave a reason for the resignation.

Deputy Defense Minister Viacheslav Shapovalov also resigned, local media reported, alleging his departure was linked to a scandal involving the purchase of food for the Ukrainian Armed Forces. Deputy Prosecutor General Oleksiy Symonenko quit, too.

Deputy head of the Presidential Office Kyrylo Tymoshenko speaks to the press at the scene of the fatal helicopter crash at a kindergarten in Brovary, Ukraine on Jan. 18. 2023.Evgen Kotenko / Future Publishing via Getty Images

In all, four deputy ministers and five regional governors were set to leave their posts, the country’s cabinet secretary said on the Telegram messaging app.

With Western allies pouring billions of dollars into Ukraine to help Kyiv’s fight against Moscow, Zelenskyy had pledged to weed out corruption which some observers have described as endemic. Zelenskyy came to power in 2019 on an anti-establishment and anti-corruption platform.

Tymoshenko joined the presidential office in 2019, after working on Zelenskyy’s media and creative content strategy during his presidential campaign.

Ukrainian soldiers eat lunch together at a base close to the frontline in the south of the country on Aug. 20, 2022. — Media reports have linked at least one official departure to a scandal involving the purchase of food for the Ukrainian Armed Forces.Bulent Kilic / AFP via Getty Images file

Last year he was under investigation relating to his personal use of luxury cars. He was also among officials linked last September to the embezzlement of humanitarian aid worth more than $7 million earmarked for the southern Zaporizhzhia region. He has denied all the allegations.

On Sunday, a deputy minister was dismissed for being part of a network embezzling budget funds. Ukraine’s infrastructure ministry later identified the dismissed official as Vasyl Lozynsky, a deputy minister there.

Oleksandr Kubrakov, the infrastructure minister, said Lozynsky was relieved of his duties after Ukraine’s anti-corruption agency detained him while he was receiving a $400,000 bribe for helping to fix contracts related to restoring infrastructure facilities battered by Russian missile strikes.

In his nightly video address, Zelenskyy said that Ukraine’s focus on the war would not stop his government from tackling corruption.

“I want to be clear: There will be no return to what used to be in the past,” Zelenskyy said.

The anti-corruption drive is vital if Ukraine wants to advance its application for membership of the European Union. To gain E.U. membership, countries must meet a detailed host of economic and political conditions, including a commitment to the rule of law and other democratic principles.

Last June, the European Union agreed Thursday to put Ukraine on a path toward E.U. membership, acting with uncharacteristic speed and unity to pull the embattled country further away from Russia’s influence and bind it more closely to the West.

Ukraine has long aspired to join NATO, too, but the military alliance is not about to offer an invitation, in part because of the country’s corruption, shortcomings in its defense establishment, and its contested borders.