Telegram has overtaken WhatsApp to become Russia's most popular messaging tool, the mobile operator Megafon said on Monday, with Russians flocking to the service as Moscow restricts some digital services.

WhatsApp owner Meta Platforms Inc. is embroiled in a Russian court case, with prosecutors seeking to label it an "extremist organization," and authorities have actively promoted Telegram as they have banned other foreign platforms such as Facebook, Instagram and Twitter.

Russia's military operation in Ukraine has added fuel to a simmering dispute between foreign digital platforms and Moscow.

Megafon, one of Russia's four main telecoms operators, said its analysis of mobile internet traffic showed that Telegram's share had jumped to 63% in the first two weeks of March from 48% in the first two weeks of February.

WhatsApp's share dropped to 32% from 48%, Megafon said.

The average Telegram user consumed 101 MB of data a day, compared to 26 MB for WhatsApp.

Founded by Russian Pavel Durov, Telegram has long been a popular news platform in Russia, with almost all major media, government entities and public figures operating content channels.

"The popularity of the service has grown against the backdrop of restrictions on access to other messengers and social networks," Megafon said in a statement. "The service started actively growing on Feb. 24."

Russia sent tens of thousands of troops into Ukraine on Feb. 24 in what it called a special operation to degrade its southern neighbour’s military capabilities and root out people it called dangerous nationalists.

Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw its forces.