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London's benchmark FTSE 100 index slid 0.9 percent to 6,941.39 points.
In the eurozone, Frankfurt's DAX 30 index shed 1.1 percent to 11,180.96 points and the Paris CAC 40 retreated 1.0 percent to 4,978.39.
Global stocks have endured sharp falls and rises this week as investors track geopolitical worries alongside positive data.