Ukraine’s popular army chief Valery Zaluzhny was called to a meeting at the president’s office on Monday and told he was being fired, two sources familiar with the matter told CNN, following weeks of growing speculation over tensions between Volodymyr Zelensky and his top commander, Paralel.Az reports citing CNN.

A formal announcement has not been made, meaning Zaluzhny was still in post as of Wednesday evening, however, a presidential decree is expected by the end of the week, one of the sources told CNN, in what would be the biggest military shakeup by Zelensky since the start of Russia’s full-scale invasion almost two years ago.

Rumors of the meeting, and Zaluzhny’s dismissal, exploded around Kyiv on Monday evening, lent credibility by a rift widely understood to have opened up between the president and his commander-in-chief following the failure of the Ukrainian counteroffensive last year.

Tensions are said to have risen in particular when Zaluzhny described the war with Russia as a stalemate, in an interview and essay with The Economist magazine in November.

On Monday, presidential spokesman Serhiy Nykyforov told CNN and others that rumors of the army chief’s dismissal were untrue. The defense ministry also put out a message on its social media channels which read, “Dear journalists, an immediate answer to everyone: No, this is not true.”

And in his daily evening address Monday, Zelensky himself made no reference at all to his army chief.

But according to one of the sources, and in line with other reports, at a small gathering at his office on Monday – also attended by Defense Minister Rustem Umerov – the president declared he had “made a decision to dismiss the commander-in-chief of the armed forces.”

In a conversation described as “calm,” Zelensky then proceeded to offer Zaluzhny a different position, which Zaluzhny declined.

Ukraine’s president then underlined his decision, saying the fact Zaluzhny had turned down the new role did not change the fact he was being removed from his current post.

CNN reached out to the president’s office on Wednesday requesting further comment but did not receive a reply.

Two names in particular are being discussed as possible successors, one of the sources, a senior military commander, told CNN.

One of them is the current head of the Defense Intelligence Directorate, Kyrylo Budanov, a 38-year-old general known to have strong ties with Zelensky and seen as representing a new generation of military leaders.

Asked by CNN in an interview on Tuesday whether he was set to become Ukraine’s new commander-in-chief, Budanov knocked it down, suggesting it was unlikely he would be speaking to CNN at that moment if such an appointment had just been made.

“We are in a war, and all sides are using all available means, including information warfare,” the military spy chief added.

The other frontrunner is Oleksandr Syrskyi, currently the Commander of Ukrainian Land Forces, the senior military commander speaking to CNN said.

Syrskyi’s office has not responded to CNN’s attempt to reach him.