SVIATOHIRSK/KYIV (Reuters) - Ukrainian forces have broken through Russia’s defences in the south of the country while expanding their rapid offensive in the east, seizing back more territory in areas annexed by Moscow and threatening supply lines for Russian troops. Making their biggest breakthrough in the south since the war began, Ukrainian forces recaptured several villages in an advance along the strategic Dnipro River on Monday, Ukrainian officials and a Russian-installed leader in the area said. The southern breakthrough mirrors recent Ukrainian advances in the east, even as Moscow has tried to raise the stakes by annexing land, ordering mobilisation,...