PARIS, Sept 4 (Reuters) - European stocks extended losses on Thursday on intensifying growth concerns after European Central Bank President Jean-Claude Trichet said the euro zone was in an episode of weak economic activity.

At 1249 GMT, the FTSEurofirst 300 <.FTEU3> index of top European shares was down 0.5 percent at 1,176.86 points, after being flat before Trichet's press conference that followed the ECB's decision to keep interest rates on hold at 4.25 percent.

Euro zone economic data point to a weakening in growth at mid-year but inflation remains high and risks are to the upside, Trichet said.

The European Central Bank also raised its forecasts for euro zone consumer price inflation in 2008 and 2009.

(Reporting by Blaise Robinson)

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Keywords: MARKETS EUROPE STOCKS/ECB