European shares tumbled in early trade on Monday as escalating tensions in Ukraine prompted investors to stick to the sidelines, Reuters reported. At 0805 GMT, the FTSEurofirst 300 index of top European shares was down 1.7 percent at 1,325.81 points, while the euro zone's blue-chip Euro STOXX 50 index was down 2.1 percent, at 3,084.69 points. "Investors had under-estimated the risks of an escalation in Ukraine, so the events over the weekend is a wake-up call for the market," said David Thebault, head of quantitative sales trading at Global Equities, in Paris.
