Russian operations are in static phase due to combat losses

 ISW:

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The Ukrainian government and military directly stated for the first time on March 24 that the Kremlin believes its invasion of Ukraine has entered a second, “protracted” phase. The head of Zelensky’s office, Myhailo Podolyak, stated that Russia seeks to turn the war into a partially “protracted phase” due to high losses in personnel and equipment and the lack of significant progress in any direction. Podolyak stated the Kremlin is changing its tactics and going on the defensive to reduce Russian casualties “to an acceptable (from a propaganda point of view) level.”[1] The Ukrainian General Staff similarly stated that the Russian military leadership is "beginning to realize that the available forces and means are not enough to maintain the temporarily occupied territories of Ukraine and are conducting defensive operations.”[2] ISW previously assessed on March 19 that Ukrainian forces have defeated the initial Russian campaign of the war and that Russian forces would likely go over to the defense.[3]

The Ukrainian General Staff stated on March 24 that the Kremlin is prioritizing restoring combat capabilities in VDV (airborne) units.[4] The General Staff reported Russian commanders are increasingly deploying reserve officers, conscripts, and obsolete armored vehicles to replace losses.[5]
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Russian forces continued sporadic and unsuccessful attacks to encircle Chernihiv on March 24. The Chernihiv City Council reported that Chernihiv “faces destruction” from heavy Russian shelling on March 24, but Russian forces did not conduct any ground offensives against Chernihiv.[15] The Ukrainian General Staff reported at midnight local time on March 23 that Russian forces are intensifying aerial reconnaissance over Chernihiv to conduct battle damage assessments and identify Ukrainian positions.[16] Social media users depicted the aftermath of a Russian special forces raid on a Ukrainian position in Chernihiv on March 23 and Russian forces are likely conducting ongoing tactical attacks on the outskirts of the city.[17] A senior US defense official told Voice of America that Russian forces are continuing efforts to encircle Chernihiv and remain 8-10km from the city center as of March 23.[18] Local Ukrainian media confirmed the Ukrainian General Staff’s report that Russian forces conducted an unsuccessful assault on Slavutych, 30km west of Chernihiv, on March 24 as part of continuing efforts to advance towards northeastern Kyiv.[19] The Ukrainian General Staff reported Russian forces, primarily including units of the 1st Guards Tank Army, did not conduct any offensive operations against Sumy in the past 24 hours but continued to shell the city.[20]
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The Russians continue to shell cities around Ukraine, but appear to lack the combat personnel to capture and control those cities.  While Ukraine has been effective in combat operations against eh Russian infantry and mechanized units. It has so far not made significant attacks against the artillery and rocket fire of the Russians.  With the Russians' problem with ground troops, it is possible that their artillery and rocket teams could also be vulnerable to Ukraine attacks, but I have seen no reports of those. 

See, also:

Russia signals scaled-back war aims, Ukrainians advance near Kyiv