*** MILITARY SITUATION ***
The Kremlin declared victory in the battle of Mariupol. Russian forces will attempt to starve out remaining Ukrainian defenders in the Azovstal Steel Plant rather than clear it through likely costly assaults. Russian President Vladimir Putin and Defense Minister Sergei Shoigu declared victory in the battle of Mariupol on April 21 despite the continued presence of Ukrainian forces in Mariupol’s Azovstal Steel Plant. In a staged, televised meeting, Putin ordered Shoigu to halt assaults on the plant to limit Russian casualties, claiming Russian forces have already captured the entirety of the city. The Kremlin will spin the (still incomplete) capture of Mariupol into a major victory in Ukraine to compensate for stalled or failed Russian offensives elsewhere.The Kremlin’s reduction of the pace of operations in Mariupol is unlikely to enable the deployment of significant combat power to support other offensive operations in the coming days and weeks. Statements from US officials that Russia has not yet removed a dozen battalion tactical groups (BTGs) from Mariupol despite Putin’s claimed victory do not capture either the status of these Russian forces or other constraints on their use.[1] ISW has consistently assessed that Russian BTGs have taken high casualties in the battle of Mariupol, are degraded, and are unlikely to possess their full complement of personnel (800-900 at full strength). As with Russian operations elsewhere in Ukraine, reporting on numbers of BTGs without additional context and analysis of the combat power of these units is not a useful evaluation of Russian forces. While it is unlikely that all 12 reported BTGs were involved in the final fighting around the Azovstal plant, it will still take some time for those units that were engaged in final assaults to disengage for redeployment elsewhere. Some portion of these Russian forces will be necessary for several other missions—including maintaining the siege of the Azovstal plant, securing the rest of Mariupol against any remaining pockets of Ukrainian forces and likely partisan actions, and possibly redeploying to support Russian forces maintaining control of southern Ukraine. Russian forces will certainly be able to redeploy some units from Mariupol to offensive operations elsewhere—but Ukrainian forces have succeeded in tying down and degrading a substantial Russian force, and the Kremlin's declaration of victory has not inherently freed up 12 BTGs worth of combat power for other operations.
-57 days into the war, and 1700 cruise and ballistic missiles later Russia has for the first time ever targeted a Dnieper bridge. There are 25 Dnieper crossing points in Ukraine. Of these the lowest 3 are in Russian hands so that leaves 22 in Ukrainian hands. The most strategically important at this moment are the crossings in the south, the 5 in Dnipro, and especially the 3 in Zaporozhye. If the Ukrainian army is decisively defeated in Donbass it can retreat in the NW direction toward Poltava or it can fall back behind the Dnieper using the Dnipro and/or Zaporozhye bridges. In the meantime these same communication lines — from the NW, through Dnipro, and through Zaporozhye — serve as the supply routes for the Ukrainian forces in Donbass.
Eliminating all 22 crossing points might be a tall order, especially since 5 of them run over dams which would be difficult to cut without risking major flooding and numerous civilian casualties. However, the number of railway crossings is just 9 and just 2 of these run over dams. By collapsing the 7 railway bridges and cutting the remaining 2 lines by repeated retargeting of marshaling grounds (rather than dams) Russia could have Ukraine split in half for railway purposes.
But Russia has not opted for this. It has been, however, targeting rail infrastructure directly behind Donbass. This perhaps forces the Ukrainians to make the last part of a supply trip with trucks but still allows them to get quite close with trains. Today, for the first time a Dnieper bridge has been targeted. The railway bridge in Zaporozhye. The lower-most Dnieper railway crossing in Ukrainian hands. There isn’t another one for 80 kilometers upstream in Dnipro.