U.S.-backed forces, Syrian army advance separately on Islamic State in Deir al-Zor

By John Davison and Rodi SaidBEIRUT/AL SHADADI, Syria (Reuters) - U.S.-backed militias and the Syrian army advanced in separate offensives against Islamic State in eastern Syria on Saturday, piling pressure on shrinking territory the group still holds in oil-rich areas near the Iraqi border.Syrian government forces fought their way to an air base on the outskirts of Deir al-Zor city that had been besieged for years by the jihadists, said a commander in the military alliance fighting in support o