Ukrainian President Petro Poroshenko has announced Sunday, June 15, a day of mourning in connection with the death of Ukrainian military men and border guards involved in the anti-terrorist operation.

"I declare Sunday a day of mourning for our military men. This is a great loss not only for their families but for the entire country. Ukraine is bewailing, but we continue to vigorously fight for peace," the presidential press service said citing the head of state.