The sweeping military shakeup that replaced Ukraine’s popular army chief this week throws up big political and military risks for President Volodymyr Zelensky as the war with Russia heads towards its third year.

Valeriy Zaluzhnyi, who led Ukraine’s war effort through the darkest days of the full-scale invasion, was replaced on Thursday by ground forces commander Oleksandr Syrskyi, who is expected to present a new military team in the coming days.

The shakeup comes as Kyiv faces ammunition shortages and uncertainty over the future of US military aid, which has been on hold for months due to Republican opposition, even as Russian forces begin to gain the upper hand on the battlefield.

“This is a risky decision, first of all, because the changes that are to take place are happening in an extremely complex environment and this may complicate the management of the troops,” Serhiy Zgurets, director of the Kyiv-based Defence Express consultancy, told Reuters.

Though Syrskyi and Zaluzhnyi have the same approaches, the new chief’s top military team has not been disclosed in full, so there could be a disruption in the management of troops in the short term, Zgurets said.

That sense of uncertainty comes as Russian troops are tightening their grip around the embattled town of Avdiivka where Ukrainian troops are dug in. Elsewhere on the eastern front, Moscow’s troops are building offensive pressure.

Ukraine has also been struggling to overhaul how it mobilises civilians into the army as it tries to regenerate manpower after its much-vaunted counteroffensive proved unable to break through Russian lines last year.

The shakeup followed months of speculation about a rift between Zaluzhnyi and the president that burst into the open late last year when the general talked of a frontline “stalemate” in interview remarks that drew a rebuke from Zelensky’s office, according to a Reuters report.

As he announced the changes on Thursday, Zelensky said there was no politics at play in the move and that he felt a broad renewal was needed in the armed forces after the setbacks for Ukraine’s ground operations in 2023.

Volodymyr Fesenko, a Kyiv-based political analyst, predicted the removal of Zaluzhnyi would hurt Zelensky’s ratings because of the general’s broad popularity.

Zaluzhnyi’s stock soared during the first two years of the war. An opinion poll in December showed he had a significantly larger share of the people’s trust than Zelensky himself.

Zaluzhnyi’s image has been spray-painted on walls around the country to mark Ukrainian battlefield victories, and after Thursday’s announcement that he was out of the top military post, messages of support for him flooded social media.

“There are a lot of dissatisfied people and the degree of emotions is quite high. Theoretically some protests are possible, but most likely it will not happen, taking into account the factor of war,” Fesenko told Reuters.

The full-scale invasion that began on Feb. 24, 2022 prompted Ukraine to introduce martial law, which rules out the possibility of holding elections. Presidential elections were due to take place next month, but with the war raging on it is unclear when they will take place.

Fesenko said that by removing Zaluzhnyi, Zelensky had essentially made the general a potential rival at future elections. He predicted that a broad political coalition would start to form around him.

Zgurets said any failures at the front, though caused by long-standing factors such as the ammunition shortage or troop fatigue, could come to be blamed on Syrskyi.

That in turn could open up the way for the criticism of the shakeup as “irrational and wrong”, he said.

Following the announcement, passers-by in central Kyiv openly questioned the appointment and voiced scepticism.

“The president probably has a better view of the situation but I want to say that horses should not be changed mid-race,” said Oleksandr Kalinichev, a doctor.