Russia is shutting down mobile internet across entire regions - Why?

Mobile internet and other forms of communication are being systematically shut down across all regions of Russia, and this has been happening for an extended period, according to Ukraine's Center for Countering Disinformation.
According to the Center for Countering Disinformation, Russians are widely reporting that there has been no internet access for six days in the Sverdlovsk and Tyumen regions. Connectivity is also reportedly down in Kurgan, Omsk, Altai Krai, Rostov-on-Don, Tatarstan, and other regions.
The outages are affecting essential services — taxi apps and automated teller machines (ATMs) are reportedly functioning poorly due to the communication issues.
The Center noted that mobile internet shutdowns in Russia first began under the pretext that they were temporary. They were introduced ahead of the Victory Day celebrations. However, over the past month, the scale and frequency of the outages have only increased.
"In reality, the systematic shutdown of mobile internet is part of a broader effort to restrict civil liberties and strengthen state control over the Russian population. The Russian authorities are trying to limit access to independent sources of information, making it easier to manipulate public opinion in the regions through propaganda," the Center for Countering Disinformation stated.
Meanwhile, Ukrainian military intelligence cyber experts recently carried out a series of successful cyberattacks targeting digital infrastructure of Russia's Federal Tax Service, Federal Customs Service, and Russian Railways (RZD).
Russia's Federal Customs Service acknowledged the DDoS attack but described it using vague language, saying that "information exchange with foreign trade operators has been complicated."
Sources within RBC-Ukraine revealed further details of the special operation.
Shortly before this, cyber units from Ukraine's military intelligence — with the support of cyber activists — successfully targeted Orion Telecom, one of the largest internet providers in Siberia.