Ukrainian President Volodymyr Zelenskyy on Thursday directed his newly installed military leadership to overhaul mobilization and reinforce the armed forces as Kyiv seeks to sustain battlefield momentum and revive negotiations to end Russia's invasion.

Zelenskyy said Commander in Chief Mykhailo Drapatyi and acting Defense Minister Yvhenii Khmara must improve recruitment after more than four years of fighting have strained Ukraine's military and made mobilization increasingly contentious.

The appointments followed a turbulent leadership shake-up in which Zelenskyy dismissed Gen. Oleksandr Syrskyi and replaced him with Drapatyi, a younger commander known for efforts to modernize the military and move away from Soviet-style command practices.

"Undoubtedly, both Drapatyi and Khmara will have to fulfill the main task facing us today after a long and exhausting war for everyone," Zelenskyy said at a news conference with Irish Prime Minister Micheal Martin, according to Ukrainska Pravda.

He identified strengthening air defenses, reforming military enlistment offices and giving mobilization "a more human face" as priorities.

The president also confirmed that former Defense Minister Mykhailo Fedorov had been offered the position of vice prime minister for defense innovation after his dismissal last week prompted demonstrations in 17 cities.

Fedorov later rejected the offer and said he would not accept another government position, intensifying the political pressure on Zelenskyy to reinstate the technology-focused former minister.

Fedorov had developed a strong following among troops and civilians by promoting drones, digitizing military systems and attempting to combat corruption in defense procurement.

His ouster and reported disagreements with Syrskyi helped spark protests that broadened into demands for changes to Ukraine's military command, according to The Associated Press.

Zelenskyy paired the personnel announcements with unusually pointed claims about Russian President Vladimir Putin, contending that Ukraine's improved battlefield position was weakening confidence in the Kremlin.

"A very toxic atmosphere," Zelenskyy said. "He alone is the reason this war began and hasn't ended. Putin alone is responsible for the losses Russians continue to suffer. His retinue understands this — they are signalling it to us and to our partners."

Zelenskyy offered no evidence supporting his assessment of Putin's inner circle, and the Kremlin has not publicly acknowledged any division over the war.

Ukraine has expanded attacks against Russian military infrastructure, logistics hubs, and energy facilities while claiming that Russian forces no longer control the initiative on the battlefield.

"Every day is difficult for our warriors, of course, and that's understandable. But the initiative is not in Russia's hands, and I think that's a good thing," Zelenskyy said Wednesday during a meeting with U.S. Ambassador to NATO Matthew Whitaker, according to the Ukrainian president's office.

Diplomatic prospects nevertheless remain uncertain after repeated attempts to bridge fundamental disagreements between Kyiv and Moscow failed to produce a settlement.

Secretary of State Marco Rubio said during meetings in Manila that the United States remains prepared to help end the war, but acknowledged that no rapid agreement is likely, according to a separate Associated Press report.

Zelenskyy said Ukrainian and U.S. teams could meet in the United States within days to discuss restarting negotiations as Ukraine simultaneously presses Western allies for weapons, financing and tougher sanctions against Russia.