The Security Service of Ukraine (SBU) has announced the opening of a criminal case on today's cyber attack on Kyivstar, which is Ukraine's largest telecom operator.

"The SBU has launched criminal proceedings into a cyber attack on one of the largest national mobile operators Kyivstar. […] One of the versions that is being considered by SBU investigators is possible involvement of Russian special services into this hacker attack," the press service of the SBU told Interfax-Ukraine on Tuesday.

The Ukrainian special service also said that as soon as the incident occurred, the SBU immediately sent it operational investigative group to the company's officer in order to document all circumstances of the attack.

In addition, SBU cyber security specialists are providing Kyivstar employees with assistance on the spot and coordinating effort of all state institutions to restore the network as soon as possible.

According to the press service, the SBU opened the case under the following eight articles of the Criminal Code of Ukraine: Article 361 (unauthorized intrusion into the work of information (automated), electronic communication, information and communication systems, electronic communication systems), Article 361-1 (development of malicious software or hardware with the purpose of illegal use, distribution or sale, as well as their distribution or sale), Article 110 (encroachment on the territorial integrity and sovereignty of Ukraine), Article 111 (high treason), Article 113 (sabotage), Article 437 (planning, preparation, unleashing and waging of war of aggression), Article 438 (violation of the laws and customs of war), and Article 255 (creation, management of a criminal group or a criminal organization and participation in them).