Ukraine's Zelenskyy replaces top general in major shake-up at pivotal moment in war with Russia

Ukrainian President Volodymyr Zelenskyy replaced his top army general on Thursday in what amounts to a major shake-up of the country's war strategy as the war with Russia grinds into its third year and Ukraine grapples with shortages of ammunition and personnel.

In a social media post, Zelenskyy said he thanked Gen. Valerii Zaluzhnyi - a military leader popular with troops and the general public - for his two years of service as commander-in-chief. "The time for such a renewal is now," Zelenskyy said.

Zelenskyy appointed Сol. Gen. Oleksandr Syrskyi, the commander of Ukraine's ground forces, to lead the army. Syrskyi, 58, has since 2013 been involved in the Ukrainian army's effort to adopt NATO standards.