Speaking as an EU-Ukraine summit came to a close in Brussels on July 10, Tusk said that a rift between the countries would only serve Russia.
Ties between Poland and Ukraine have become strained over their shared history.
Radio Poland: Polish, regional security depends on Warsaw-Kyiv ties, says Tusk
This picture taken and released by the Ukrainian presidential press-service on July 8, 2018 shows Ukrainian leader Petro Poroshenko paying his respects during the opening of a memorial to Ukrainians killed by Polish partisans during the ceremony in the Polish village of Sahryn, 125 kilometers (77 miles) across the border.The presidents of Poland and Ukraine held separate ceremonies marking 75 years since a WWII-era ethnic conflict between their nations claimed thousands of lives, as a row over history continued to sour relations between the neighbours. Discord over the TheVolhynia massacres between 1943 and 1945 has led to a diplomatic chill between Kiev and Warsaw, whose relations deteriorated after the nationalist Law and Justice (PiS) party came to power in Poland in 2015. Polish President Andrzej Duda attended a mass commemorating the Polish victims of the conflict in Lutsk, a city in Ukraine's western Volhynia region.
