Memorial events have been organized by local Polish diplomats in the cities of Lutsk and Lviv in the territory of Ukraine.
A wreath-laying ceremony will also be held at a Warsaw monument that honours victims of wartime killings known as the Volhynia Massacres on Sunday evening.
The peak of the massacres took place in July and August 1943 in Volhynia and Eastern Galicia, in what was then German-occupied Poland.
On July 11, 1943, the day of the worst bloodshed, Ukrainian nationalists attacked 100 villages largely inhabited by Poles in what was then Nazi-occupied eastern Poland and is now western Ukraine.
The massacres were part of an operation carried out by the Ukrainian Insurgent Army (UPA).
The total number of victims from the Polish minority living there has been calculated at 100,000.
The National Day of Remembrance of Victims of Genocide perpetrated by Ukrainian nationalists on the citizens of the Second Republic of Poland was established by the Sejm lower house of parliament on 22 July 2016.
(ał)
Source: IAR