Ukraine's sacked the head of the army's medical services department and two senior cyber defense officials Monday.
President Volodymyr Zelensky has dismissed the head of the army medical department.
Major General Tetiana Ostashchenko will be replaced by Anatoliy Kazmirchuk, Zelenskyy said in his evening video address on Sunday.
Kazmirchuk was previously head of the national military hospital in Kyiv.
"A fundamentally new level of medical support for our military is needed," Zelenskyy said, without explaining his decision any further.
Ostashchenko was appointed commander of the Ukrainian army's Medical Forces Command in 2021 – before the start of Russia's all-out invasion. She was the first woman to hold this position.
Complaints from military doctors and paramedics about her work have been mounting. Around a week ago, the internet portal Ukrainska Pravda reported that Defence Minister Rustem Umerov was considering requesting the dismissal of Ostashchenko.
Two senior cyber defense officials were sacked Monday, a government official said, as prosecutors announced a probe into alleged embezzlement in the government's cyber security agency.
Yurii Shchyhol, head of the State Service of Special Communications and Information Protection of Ukraine (SSSCIP), and his deputy, Viktor Zhora, were dismissed by the government, senior cabinet official Taras Melnychuk wrote on Telegram.
Melnychuk, the cabinet's representative to parliament, did mention the reasons for the dismissals. Neither man nor their lawyers could be reached for comment.
The SSSCIP is responsible for securing government communications and defending the state from cyber attacks.
News of the firings came less than an hour before anti-corruption prosecutors said they were investigating the head and deputy head of the SSSCIP over their alleged roles in a six-person plot to embezzle 62 million UAH ($1.72 million) between 2020 and 2022.
Prosecutors did not name either official. The SSSCIP did not immediately respond to a written request for comment on the investigation.
Authorities suspect the officials of buying software at an inflated price from two companies allegedly under their control in a sale that had been closed to other bidders, Ukraine's National Anti-Corruption Bureau said.
Ukraine has stepped up efforts to curtail corruption as it pursues membership in the European Union, which has made the fight against graft a key prerequisite for negotiations to begin.
Recent targets for investigation have included a billionaire former patron of Zelenskyy and the ex-head of Ukraine's Supreme Court. Both have denied wrongdoing.
In September, Shchyhol told Reuters that Russian spies are using hackers to target computer systems at law enforcement agencies to identify and obtain evidence related to alleged Russian war crimes.
