MOSCOW (Reuters) -Russia's ejection of Ukrainian troops from the Kursk region ends the biggest incursion into Russian territory since World War Two, removing another barrier to a peace deal Moscow was reluctant to conclude with so many enemy troops on its soil. The day after Moscow announced the completion of the Kursk operation, President Vladimir Putin declared a unilateral three-day ceasefire to mark the 80th anniversary of the victory of the Soviet Union and its allies in World War Two. Two Russian sources told Reuters on condition of anonymity that settling the war while Ukrainian troops were in Kursk was not acceptable to the Kremlin.