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Kyivstar has stabilized voice communication in Kyiv, the company's chief product director Mykhailo Nestor reported on Facebook.

"Voice is stabilizing all over Kyiv, including the right bank. Reboot [your devices]. We are working on 3/4G," wrote Nestor.

As of Wednesday morning in Kyiv, the ability to make calls was not available to all users. On Wednesday evening, the CEO of the company Oleksandr Komarov announced plans to restore the rest of the services overnight.

Kyivstar restored voice communication on Wednesday evening after the cyber attack that began on Tuesday morning.

Personal data of Kyivstar subscribers have not been compromised, Iryna Lelichenko, the operator's spokeswoman, said in a comment to LIGA.net. The data is safe, and the systems in which it is stored were not affected by the hacker attack, the company assured.

Russian hackers from the Solntsepek group claimed responsibility for the cyber attack on the Kyivstar mobile operator, by announcing this in their Telegram channel.