By Max Hunder and Tom Balmforth KYIV (Reuters) -Ukraine was set to pull its troops from the ruined city of Sievierodonetsk after weeks of street fighting and bombardment, the regional governor said, in what would be a significant gain for Russia as it grinds out its offensive in the east. Russian troops also occupied a town about 10 km (6 miles) further south, both sides said on Friday, as Moscow closed in on the last slivers of Ukrainian-held territory in the industrial region of Luhansk. Moscow said it had encircled about 2,000 Ukrainian and what it called foreign troops in the area. Reuters…