Russia is considering allowing over-40s to join the army in a bid to bolster its invasion.
Politicians in the State Duma said they will consider a bill on Friday to raise the age of enlistment in order to gain experienced soldiers.
A statement from the Duma said: “For the use of high-precision weapons, the operation of weapons and military equipment, highly professional specialists are needed.
“Experience shows that they become such by the age of 40–45.”
Previously, only Russians aged 18-40 and foreigners between 18-30 could enter the military.
This comes as Ukrainian officials have claimed Russia has lost 28,000 troops since the invasion began - although this has not been verified by western sources.
Latest Defence Intelligence update on the situation in Ukraine - 20 May 2022
— Ministry of Defence 🇬🇧 (@DefenceHQ) May 20, 2022
Find out more about the UK government's response: https://t.co/AgtCk64rRw
🇺🇦 #StandWithUkraine 🇺🇦 pic.twitter.com/W938cA16hU
Ukrainian forces have also pushed Russian troops back in the northeastern region of Kharkiv, the country’s second-largest city.
While some territory has been reclaimed, the Ministry of Defence (MoD) has said up to 1,700 Ukrainian soldiers have surrendered from the Azovstal steelworks.
“As many as 1,700 Ukrainian soldiers are likely to have surrendered from the Mariupol Azovstal steel factory. An unknown number of Ukrainian forces remain inside the factory,” the ministry wrote on Twitter.
"Staunch Ukrainian resistance in Mariupol since the start of the war means Russian forces in the area must be re-equipped and refurbished before they can be redeployed effectively.
“This can be a lengthy process when done thoroughly.”
The steelworks has been a final stronghold for forces attempting to prevent the occupation of the southern city of Mariupol.
After securing the city, the MoD reports Russian forces will then reinforce the Donbas region.
Speaking during his nightly address from Kyiv, Mr Zelensky said Vladimir Putin’s army had turned the region into “hell” as intense fighting raged on.
“[There are] constant strikes on the Odesa region, on the cities of central Ukraine. The Donbas is completely destroyed,” he said.
“All this has not and cannot have any military explanation for Russia. This is a deliberate and criminal attempt to kill as many Ukrainians as possible. Destroy as many houses, social facilities and enterprises as possible.”
Russia was forced refocus its offensive in the east of the country last month after failing to claim Kyiv and parts of central Ukraine.
