European shares resumed their sell-off on Tuesday after a slump in the previous session caused by worries over Greece, with energy stocks declining as the oil price hit new lows, Reuters reported. The pan-European FTSEurofirst 300 index, which had fallen 2.3 percent on Monday, retreated by 0.6 percent while the euro zone's blue-chip Euro STOXX 50 index -- which slumped 3.7 percent on Monday -- also fell by a similar amount. The STOXX Europe 600 Oil & Gas Index weakened by 1 percent as oil touched new 5-1/2 year lows on Tuesday, following a 5 percent plunge in the previous session as a slew of bearish factors added to supply woes.