Telegram founder commits to Ukraine user privacy
In a Telegram post, Pavel Durov, who lives in Dubai, wrote: "I stand for our users no matter what. Their right to privacy is sacred - now more than ever."
Telegram was Ukraine's most popular messaging app - the Observer newspaper reported.
But some experts have raised concerns about the security of users' data.
Moxie Marlinspike, who developed the encryption used by rival platforms Signal- which he created - and WhatsApp, tweeted many users thought Telegram was an encrypted app, but it was "by default a cloud database with a plaintext copy of every message everyone has ever sent/received".
Telegram maintains everything stored on its cloud is securely encrypted, however while all of its data is protected only some of its features use end-to-end encryption.
'Any cost'
So-called Secret Chats, voice calls and video calls are end-to-end encrypted on Telegram so cannot be read by the company.
But in theory the company could access other encrypted content stored on Telegram's servers.
And there have been concerns it could be forced to share user data with Russia.
But on Monday, its founder wrote a Telegram post the company said was "a commitment to protect user data at any cost".
In the post, Mr Durov stressed his Ukranian heritage, on his mother's side, writing the "tragic conflict is personal both to me and Telegram".
"Some people wondered if Telegram is somehow less secure for Ukrainians, because I once lived in Russia," he wrote.
"Let me tell these people how my career in Russia ended."
Nine years ago, he had been chief executive of VK, a social network popular in Russia and Ukraine, Mr Durov wrote.
"In 2013, the Russian security agency, FSB, demanded that I provide them the private data of the Ukrainian users of VK who were protesting against a pro-Russian president," he said.
"I refused to comply with these demands, because it would have meant a betrayal of our Ukrainian users.
"After that, I was fired from the company I founded and was forced to leave Russia."
Billion downloads
As a result, he had lost his company and his home - but he would do it again.
"I smile with pride when I read my VK post from April 2014, which shows the scanned orders from the FSB and my trademark response to them - a dog in a hoodie," Mr Durov wrote.
Last year, Telegram, based in Dubai, reached a billion downloads. Read More…