Ukraine’s top general has doubled down on a confrontation with Ukrainian President Volodymyr Zelenskyy over military leadership, escalating a power struggle in Kyiv at a critical time in the war against Russia’s invasion.

Valeriy Zaluzhnyi, whose future as commander-in-chief of the armed forces is hanging in the balance, wrote in an opinion piece for CNN that bureaucrats are holding back Ukraine’s defense industry and "a new philosophy of training and warfare” is needed in 2024.

Zaluzhnyi refused to step down Monday at a meeting with Zelenskyy as the president seeks to reinvigorate his military after Ukraine’s counteroffensive fizzled in the fall, according to people familiar with the discussions. That has left the two men at odds while military support from the U.S. is increasingly at risk.