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, Ednews reports.

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.

But according to one of the sources, 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.