The arrest of maverick entrepreneur Pavel Durov has drawn global attention to the importance of his messaging app Telegram for Russian troops and propagandists as Moscow's war against Ukraine grinds into its third year.
Since the Kremlin invaded Ukraine in 2022, Telegram, which has over 900 million active users, has emerged as a crucial platform used by pro-war bloggers to justify Moscow's invasion and sow disinformation in Ukraine and the West.
It is also used as a tool by Ukraine -- President Volodymyr Zelensky posts his daily nightly address on Telegram -- although for Kyiv the app appears to lack the same military significance.
Observers say that in the absence of a modern battlefield management system, Russian troops have also grown to rely on Telegram in their day-to-day operations, using the encrypted app for everything from the transfer of intelligence to course-correcting artillery attacks and guiding Iskander missile systems.
The arrest of the Russian-born Telegram chief in France has sent shockwaves among Russian authorities and war propagandists who fear the popular app will be compromised if Durov hands the encryption keys over to Western intelligence.
"They're terrified," Ivan Filippov, who studies Moscow propaganda, said, referring to influential pro-war bloggers with tens of thousands of followers.
If Western intelligence gets a backdoor into Telegram "it would be an absolute disaster" for Russia, Filippov told AFP, summing up their thinking.
"It's about management on the ground," added Filippov, who runs a widely-followed Telegram channel.
A self-proclaimed libertarian, Durov has championed confidentiality on the Internet. Moscow tried to block Telegram in 2018, but abandoned those efforts two years later.
Pro-war blogger Andrei Medvedev said Telegram had emerged as the "main messenger" of Russia's invasion against Ukraine.
"This is an alternative to classified military communications," Medvedev said.
Alexei Rogozin, head of the Centre for the Development of Transportation Technologies, said many joked that Durov's arrest was tantamount to "the arrest of the chief of communications for the Russian armed forces –- this is how troop battlefield management depends on Telegram today."
"Intelligence transfer, artillery course-correction, video streaming from copters and many other things are indeed often carried out with the help of Telegram," said Rogozin, the son of the controversial former Russian space agency chief, Dmitry Rogozin.
- 'Stuck in the past' -
Mykhailo Samus, director of the New Geopolitics Research Network, a Kyiv-based think tank, said that while Russia has command and control systems, "they are not efficient on the battlefield".
"The Russian army is stuck in the past," Samus told AFP.
Samus pointed out that the Ukrainian army has successfully relied on Delta, a battlespace management system developed by Ukrainians in collaboration with NATO. Delta has earned high praise from the Western military bloc, which called the system "ground-breaking."
While military observers do not expect Durov's arrest to have any immediate impact on Russia's war in Ukraine, it might spur the development of alternative encrypted communications systems in Russia.
Medvedev said it was now "vital" for the Russian army to create a proper military messenger as "it is difficult to predict how long Telegram will remain the way we know it" or "remain at all".
- 'A tool of Putin's war' -
France issued an arrest warrant for Durov in a preliminary investigation into alleged offences including fraud, drug trafficking, cyberbullying, organised crime and promotion of terrorism.
The Kremlin warned Paris on Tuesday against trying to intimidate Durov.
"The charges are indeed very serious, they require no less serious evidence," Kremlin spokesman Dmitry Peskov said.
The team and supporters of the late Russian opposition leader Alexei Navalny also actively use Telegram, and Durov's detention has split the anti-Kremlin opposition.
Many Kremlin critics called France's actions an assault on the freedom of speech, while others said Telegram should become more responsible.
Bulgarian journalist Christo Grozev, who has investigated Russian intelligence services and was close to Navalny, said Russian domestic security service FSB and the GRU military intelligence have used Telegram to recruit saboteurs and plot "terrorist acts".
"I believe that France has no right to treat him any differently than anyone who runs a marketplace selling drugs and child porn, and refuses to remove such services," Grozev told AFP, referring to Durov.
"And this has nothing to do with the freedom of expression or protection of user rights," added Grozev.
The Free Russia Forum, co-founded by Kremlin critic and former world chess champion Garry Kasparov, said Durov -- "willingly or unwillingly" -- has allowed Telegram to become a "weapon of war."
"No matter how Durov's French saga ends, we hope that Telegram will stop being a tool of Putin's war."
By Anna Smolchenko