KYIV (Reuters) – Ukraine on Sunday suspended operations at one of the seven checkpoints to territory in the eastern Donbass region controlled by Russia-backed separatists, due to heavy shelling, the Ukrainian military said. Incidents of shelling across the line dividing government forces and separatists increased sharply last week, in what the Ukrainian government called a provocation. Kyiv’s Western allies say Russia is preparing to invade Ukraine and are concerned that the escalation might be used as a pretext. Russia denies any plans to attack its neighbour, while Ukraine strongly denied su…