By Natalia Zinets KYIV (Reuters) -Ukraine said its forces were still trying to evacuate civilians from embattled Sievierodonetsk on Tuesday after Russia destroyed the last bridge to the city, Moscow’s main target in its battle for control of eastern Ukraine. Ukrainian forces were holding out against the Russians after ground changed hands several times over the past few weeks, enduring what President Volodymyr Zelenskiy described as “painful” losses. “But we have to hold strong … The more losses the enemy suffers, (the) less strength it will have to pursue its aggression,” Zelenskiy said in …