Ukraine's President Volodymyr Zelenskyy replaced the commander of the military's land forces on Friday, putting Major General Mykhailo Drapatyi in charge, as Russia notches up gains in the east and Kyiv's troops face manpower shortages.

Zelenskyy said "internal changes" were needed as he announced the 42-year-old would replace Lieutenant General Oleksandr Pavliuk, who took the helm of the land forces in a major shake-up in February 2024.

"The main task is to increase noticeably the combat efficiency of our army, ensure the quality of servicemen training, and introduce innovative approaches to people management in Ukraine's Armed Forces," Zelenskyy said.

"The Ukrainian army needs internal changes to achieve our state's goals in full," he said on Telegram after meeting his top military and government officials.

Drapatyi is well respected in the army and military analysts praised his appointment. Drapatyi took command of the Kharkiv front in May and managed to stop the Russian offensive in the northeast, stabilizing the front.

Zelenskyy also said that he appointed Colonel Oleh Apostol, commander of the 95th separate air-assault brigade, as a deputy to army chief Oleksandr Syrskyi.

He praised both Drapatyi and Apostol, saying "they had proved their efficiency on the battlefield."

Ukraine is on the back foot on the battlefield as it fights a much bigger and better-equipped enemy 33 months after Russia's full-scale invasion in February 2022.

The Russian forces are steadily advancing in the eastern Donetsk region. Syrskyi, the army chief, said on Friday he would strengthen troops deployed on the eastern front with reserves, ammunition, and equipment as he visited two key Ukrainian-held sites in the Donetsk region.

Ukraine has also lost about 40% of the territory it captured in Russia's Kursk region in a surprise incursion in August, as Russian forces have mounted waves of counter-assaults.

The head of the land forces oversees mobilization efforts during the war.

Military analysts say Ukraine's military is experiencing manpower shortages, making it harder to rotate troops out of the more than 1,000 kilometers (620 miles) of frontline or to build up reserve forces.