Russia tries to get Belarus into war, moves support units into combat

 ISW:

...

The Ukrainian General Staff continued to warn on March 20-21 that Russia seeks to bring Belarus into the war. The Ukrainian General Staff reported at midnight local time on March 20 that “there is a high probability” of Russian provocations against Belarus to bring Belarus into the war in Ukraine and create a new axis of advance into western Ukraine.[1] Belarus evacuated its embassy in Kyiv to Moldova on March 19 in response to what it claimed were “unbearable working conditions.”[2] The Ukrainian Security Service (SBU) also reported on March 21 that it detained a Belarusian spy who was examining Ukrainian deployments and equipment in Volyn Oblast.[3] Belarusian social media users additionally observed Belarusian military equipment in Rechista (in the Brest region), 7km from the Ukrainian border, on March 21.[4] The Kremlin likely seeks to bring Belarus into the war in Ukraine to reinforce Russian forces, but Belarusian President Lukashenko likely continues to resist Russian pressure. A new Russian or Belarusian axis of advance into Western Ukraine would be unlikely to succeed. Russian and Belarusian forces would face staunch Ukrainian resistance and similar, if not greater, morale and logistics issues to Russian forces elsewhere.

The Ukrainian General Staff stated for the first time on March 21 that Russia is deploying unspecified support units to “direct combat operations” and said that Russia continues to deploy reserves from the Central and Eastern Military Districts (CMD and EMD).[5] The Ukrainian Military Intelligence Directorate (GUR) provided further details on conscription measures in the DNR and LNR on March 21. They reported that Russian authorities are increasing the conscription age from 55 to 65 and aggressively recruiting 18-year-old students. The GUR reported conscripts in DNR/LNR forces are supplied with military equipment from the 1970s.[6] Local social media imagery depicted new conscripts equipped with the Mosin-Nagant bolt action rifle—which has not been produced since 1973 and was first produced in 1891.[7]

The Ukrainian General Staff reported on March 21 that Russian forces in Ukraine are in “dire need of repairing and rebuilding damaged weapons and military equipment,” and stated a lack of foreign-made components is slowing production in key Russian military industries.[8] The Ukrainian General Staff also said that Russia is decreasing its use of manned aircraft and replacing them with unmanned aerial vehicles (UAVs), likely due to continuing losses and wear and tear on both airframes and pilots.[9]
...

These moves by the Russians are move evidence of the casualties that are attriting the Russian forces.  Pulling troops from support units means they likely had little combat training and it also degrades the support efforts.  

The Russian weapons and support vehicles have also taken a beating in this war.  It appears to some US observers that the vehicles were poorly designed and built and poorly maintained.  Some appear to have been pulled from storage and things like the tires had deteriorated while in storage and easily broke down further handicapping their struggling logistic efforts.  I suspect that their maintenance on manned aircraft may be a problem too besides the combat losses to Stinger missiles supplied by the US.

Their expansion of the conscription age looks like a historical comparison to other countries in a losing effort.  The attempt to pull Belarus into the war also looks like desperation.  Neither Belarus nor Russia has provided a logical reason for going to war with Ukraine.