Passage: The response of non-ethnic Poles to the situation added a further complication. Many Ukrainians, Belarusians and Jews welcomed the invading troops. Local Communists gathered people to welcome Red Army troops in the traditional Slavic way by presenting bread and salt in the eastern suburb of Brest. For this occasion a sort of triumphal arch was made of two poles, decked with spruce branches and flowers. A banner, a long strip of red cloth with a slogan in Russian, glorifying the USSR and welcoming the Red Army, crowned the arch. The local reaction was mentioned by Lev Mekhlis, who told Stalin that the people of West Ukraine welcomed the Soviets "like true liberators". The Organization of Ukrainian Nationalists rebelled against the Poles, and communist partisans organized local uprisings, such as that in Skidel.

Question: What nationality are the protesting nationalists?
Ukrainian