Ukraine will demand at the Minsk meeting of the 'Normandy Four' foreign ministers that nearly 60 prisoners held in districts of Donetsk and Luhansk regions uncontrolled by Kyiv be released, Verkhovna Rada First Vice-Speaker and Ukrainian representative to the humanitarian subgroup of the Trilateral Contact Group Iryna Gerashchenko said.

"Ukraine insists on the soonest release of hostages, and we will prioritize this issue. We demand that 57 hostages confirmed by the individual districts be released right now. Ukraine will also raise the question of hostages held in Russia," she said on Facebook on Tuesday before a meeting of the 'Normandy Four' foreign ministers in Minsk.

According to the Ukrainian Security Service, the self-proclaimed republics are holding 108 Ukrainians hostage, but have confirmed the detention of only 57 persons as of yet, Gerashchenko said.

"We also insist on the immediate access of the International Committee of the Red Cross (ICRC) to the search for the missing; as of today, there are 495 names on that dreadful list," she said.

Ukraine is worried about daily violations of the truce and "will present convincing facts of those violations" and of the presence of Russian military hardware in Donbas, Gerashchenko said.

"Another important subject is an environmental catastrophe caused by Russia in Donbas, from water supply [there has been no water supply to Toretsk for a week] to similar situations, which the minister and the Ukrainian delegation will speak about today," Gerashchenko said.