Ukraine's biggest mobile operator suffers huge hacker attack: What we know

Ukraine's Kyivstar Hacked: We are working to repair the outage and cooperating with law enforcement bodies, the company said.

Ukraine's biggest mobile network operator Kyivstar said that it was the victim of a powerful hacker attack which temporarily knocked out its cellular and internet signal. The company is owned by Amsterdam-listed mobile telecoms operator Veon.

Ukraine's Kyivstar Hacked: Ukraine's Kyivstar has been hacked. (Representational)

We are working to repair the outage and cooperating with law enforcement bodies, the company said. Meanwhile, the co-founder of Monobank, a major Ukrainian payment system, saidthat his company was currently suffering a distributed denial of service (DDoS) attack but everything was "under control".

"The most important thing is that the personal data of users has not been compromised," Kyivstar said in its statement. It also promised to compensate customers for loss of access to services but did not say who it believed to be responsible.

Ukrainian state bodies and companies have often accused Russia, which is at war with Ukraine, of orchestrating cyber attacks.