European shares fell early on Tuesday, snapping a three-day winning run and mirroring losses on Wall Street where cautious comments from U.S. billionaire investor Carl Icahn at a Reuters summit prompted some late losses, Reuters reported. The FTSEurofirst 300 index of top European shares was down 0.4 percent at 1,298.66 points, after gaining 1.6 percent in three sessions. Euro zone banks were among the biggest losers, with BNP Paribas down 1.2 percent and Bankia down 1.1 percent. Icahn, speaking at the Reuters Global Investment Outlook Summit, said the stock market could see a "big drop" because earnings at many companies were fuelled more by low borrowing costs than management efforts to boost results. The FTSEurofirst 300 has gained 17 percent over the past five months, boosted by an improvement in Europe's macroeconomic backdrop as well as ample liquidity from central banks.