One hundred and twenty people are still held in by militants in captivity in Donbas, Ukrainian President Petro Poroshenko has said.

"After months of negotiations, we still cannot free more than 120 Ukrainians from captivity in Donbas," the president said at the 'Ukraine's Battle for Freedom Continues' forum in Washington on Thursday.

According to him, the International Committee of the Red Cross is banned from visiting them and is prohibited from searing for about 800 missing persons.

The president also said at least 11 Ukrainian citizens have become political prisoners in Russia. "Some of them, including [captive Ukrainian pilot, Member of Parliament] Nadia Savchenko, are in critical health," he added.