The new chief of Ukraine's armed forces Oleksandr Syrskyi has said one of his top priorities is to step up the use of drones and electronic warfare.

Syrskyi said this technology was key to Ukraine's future success in liberating occupied territory from Russian forces.

"Only by changing and constantly improving the means and methods of warfare will we be able to successfully pursue this path," he wrote on Telegram.

Syrskyi described the rapid and efficient supply of front-line troops as equally important, adding that, "the lives and health of the soldiers were and remain the most important value of the Ukrainian army."

He said military leaders want troops to be rotated from the front more often, and be given more rest periods and training.

The replacement of exhausted troops and further mobilization has been the subject of heated debate in recent months.

Syrskyi replaced former military chief Valerii Zaluzhnyi, who was fired on Thursday after nearly two years of conflict and following the failure of Ukraine's counteroffensive.

Zaluzhnyi and Ukrainian President Volodymyr Zelenskyy fell out after the armed forces commander warned of endless casualties and destruction without new technology.

Zaluzhnyi had also recently called for up to half a million draftees, which the president was against.

The former military chief has been awarded the honorary title of Hero of Ukraine.