Russian lawmakers approved legislation on Tuesday that's likely to raise the upper age limit for mandatory military service and ban draftees from leaving the country as Moscow seeks to expand its pool of military reserves amid staggering losses in President Vladimir Putin's stalled war in Ukraine.

Under current Russian laws, all men aged between 18 and 27 must serve one year of conscription service. New amendments to legislation that passed a final hearing Tuesday in the Duma, Russia's lower house of parliament, would raise the upper age limit for compulsory service to 30 from next year while keeping the lower limit of 18 unchanged.

Conscripts can't immediately be sent into battle — they officially must undergo at least several months of training before they can sign up to go to the front lines. However, Russian rights groups have said new conscripts have been pressured into signing contracts with the army or otherwise forced to take part in the war in Ukraine.

The war has claimed thousands of lives on both sides, but it became apparent soon after the full-scale invasion began in February 2022 that Russian forces and leaders had likely expected an easier fight.

"The Russian forces have some really significant and deep systemic problems at the moment in their efforts," U.K. Minister of Defense Ben Wallace said in March, adding that the "latest U.S. assessments I have seen now put [Russian] casualty figures over 220,0000 of dead or injured."

U.S. officials have said this year's front-line battles, particularly around the fiercely contested town of Bakhmut, have been particularly brutal for Russia, and Ukrainian commanders in the region told CBS News they were facing wave after wave of Russian mercenaries who seemed poorly equipped for the fight.

The proposed changes to Russia's draft laws represent a notable deviation from the original amendments supported by President Vladimir Putin in December, which proposed raising the age limits gradually from 18-27 to 21-30 over three years — a proposal seen widely as a way to address public concern over young, untrained men being sent to the front lines in Ukraine.

"The wording of the draft law has changed due to the fact that the demographic situation is serious, it affects the size of the mobilization resource, and in order for us not to fall behind, such a wording is needed," co-author of the bill and chair of the Duma's Defense Committee Andrei Kartapolov was quoted as saying by Russia's Interfax news agency.

Kartapolov added that the age limits were expanded to ensure a consistent number of conscripts each year, "so there would be a pool of people to draw from."

This year's spring recruitment campaign, which Karapolov noted as an example of the kind of numbers the military wants to see each year, saw 147,000 men drafted.

Russia's upper house of parliament, the Federation Council, was set to vote on the changes Friday, although the speaker of the Council has already said it will support the measure. Putin's signature is also required for the new age parameters to come into force, but there was little doubt the bill would land on the president's desk and be quickly signed into law.

The measure is part of a wider overall of Russia's army initiated by Defense Minister Sergei Shoigu last year that seeks to address a lack of trained soldiers for the war in Ukraine.

Under the proposed changes, the Russian Armed Forces would swell their ranks by 30%, from 1.15 million to 1.5 million service members, over the next few years.

Shoigu has also backed proposals to allow men carrying out their mandatory service to immediately sign up to fight in Ukraine.

The proposed law would also ban conscripted men from leaving Russia after the military issues them a draft notice — a measure meant to crack down on draft evasion. A massive Russian military mobilization effort last autumn sparked an exodus of fighting-age men out of the country.

Putin also signed a separate law Monday that will gradually raise the upper age limit for the mobilization of reservists by five years. When the staged changes are complete in several years, the military will be able to call up senior officers from reserve up to the age of 65, and junior officers up to 60. Reservists of all other ranks will be subject to mobilization up to the age of 55.

For high-ranking reserve officers, the age limit of mobilization remains unchanged at 70. The amendments also allow the Russian military to contract foreign citizens in the country up to the age of 52.

In:
• War
• Ukraine
• Russia
• Vladimir Putin