In the clearest sign yet that a cease-fire is taking hold, Ukraine’s army said it would start pulling back heavy weapons from the front lines of its 10-month conflict with Russia-backed militants. Ukraine announced the move Thursday after reporting two days of reduced shelling and no deaths among servicemen. The start of the withdrawal marks the second stage of an agreement struck two weeks ago, aimed at ending the fighting that has cost more than 5,000 lives and created the worst tensions between Russia and the West since the Cold War. Officials in Kiev said shelling was still taking place and expressed concerned that separatists want to continue recent advances and seize more territory, such as the industrial port city […]