Ukrainian presidential adviser Yuri Biryukov said that as many as 1,723 Ukrainian servicemen has been officially reported killed in the force operation in eastern regions, however this statistics doesn’t include those whose death has not been officially confirmed and who are reported missing, Russia Today said.

"As of 18:36 on June 7, 2015, overall human losses in the Ukrainian army were 1,723 people. But there are more, not much more, but more losses. Why? Because a servicemen cannot be recognized as killed at the state level until we have a report and a death certificate. Until we have the identified body," he wrote on his Facebook account on Sunday.

He also noted that the country’s military command cannot underrate the army’s losses.

"I just cannot see from the technical point of view how the losses could be underrated when there are relatives, Facebook, volunteers. The only option that once existed was not to mention losses among volunteers who joined the army," he wrote.

Earlier, Ukrainian President Pyotr Poroshenko said that as many as 1,800 Ukrainian servicemen and about 7,000 civilians had been killed during the armed conflict in eastern Ukraine.