Receive Breaking News updates as they occur
By Aleksandar Vasovic and Alissa de Carbonnel SLAVIANSK/YENAKIEVO, Ukraine (Reuters) - At least three people were killed in a gunfight in the early hours of Sunday near a Ukrainian city controlled by pro-Russian separatists, shaking an already fragile international accord that was designed to avert a wider conflict. The incident triggered a war of words between Moscow and Ukraine's Western-backed government, with each questioning the other's compliance with the agreement, brokered last week in Geneva, to end a crisis that has made Russia's ties with the West more fraught than at any time since the Cold War. The separatists said armed men from Ukraine's Right Sector nationalist group had attacked them. Failure of the Geneva agreement could bring more bloodshed in eastern Ukraine, but may also prompt the United States to impose tougher sanctions on the Kremlin - with far-reaching consequences for many economies and importers of Russian energy.