The Security Service of Ukraine (SBU) has reported that nearly 400 Ukrainian citizens are held captive by the militants in Donbas and the state authorities do their best to exchange them under "all for all" principle, the SBU chief's advisor Markiyan Lubkivsky said.

"The reports allegedly '16 military men, which have been returned to Ukraine were the last hostages on the territory of the so-called Donetsk People's Republic' are not true. We hope for returning of almost 400 our compatriots," Lubkivsky wrote on Facebook on Monday evening.

Besides, he said that "Ukrainian party adheres to the principle 'all for all' when returning our soldiers, officers, civilians back home" and the Ukrainian authorities are ready to act under such principle in future as well.

When commenting on the statements made by the representatives of 'Donetsk People's Republic' (DPR) allegedly Ukraine holds 1,379 militants of 'DPR' in captivity, the advisor said it doesn't respond the reality.

"Despite all complication of the process of the mutual handling of the persons, we continue this process and won't stop until the last Ukrainian comes back home," he said.