What happened. Russia developed the Plan B after blitzkrieg’s failure and looking for leverages to force Ukrainian authorities to accept neutrality between Russia and the West.
The source. This information appeared in The Wall Street Journal’s article that refers the high-level US officials.
Detaiils. According these officials’ data, Kremlin moved to a new strategy for ensuring the key territory goals. Russia tries to find leverages to force Kyiv to accept neutral status between the Russian Federation and western countries.
Particularly, Putin will try to force to accept Russian claims for Eastern and Southern territories of Ukraine. Russia is going to ensure the overland bridge between the West of Russia and the Crimean peninsula, and also extend its control over Donbas. Putin will probably continue military pressure, including strikes on Russian cities.
WSJ mentiones that Russian troops face great trouble with logistics, personal losses and ammunition reduction.