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EMERGING MARKETS-Mexican stocks and currency fall after Yellen economy comments

By Bruno Federowski SAO PAULO, Oct 14 (Reuters) - Mexico's stock index and currency fell on Friday after Federal Reserve Chair Janet Yellen laid out deepening concerns at the Fed that U.S. economic potential is slipping and may need aggressive steps to rebuild it.

Yellen's comments, which were posed as questions that need more research, rattled investors.

Mexico's IPC stock index fell 0.08 percent, while the peso weakened 0.47 percent to 19.02 per U.S. dollar.

Brazilian stocks rose more than 1 percent after state-controlled oil company Petróleo Brasileiro SA announced a fuel price cut and a new pricing policy.

Petrobras said it will reassess prices on a monthly basis to follow global markets more closely, without falling below international prices, turning the page on years of politically driven pricing that cost the company billions.

Though lower short-term fuel prices tend to hurt revenue, increased transparency could help lure partners in refining projects, BTG Pactual said in a sales note.

Demand for emerging market assets has been tepid in recent days as expectations grow that the Federal Reserve will raise interest rates in December.

Key Latin American stock indexes at 2154 GMT: Stock indexes daily % YTD % change change Latest MSCI Emerging Markets 897.03 0.72 12.96 MSCI LatAm 2496.13 1.14 36.41 Brazil Bovespa 61767.22 1.06 42.49 Mexico IPC 47701.45 -0.08 10.99 Chile IPSA 4141.16 0.38 12.53 Chile IGPA 20746.20 0.43 14.29 Argentina MerVal 17414.89 1.04 49.16 Colombia IGBC 9946.92 -0.53 16.37 Venezuela IBC 13552.60 0.66 -7.10 (Reporting by Bruno Federowski and Noe Torres; Editing by Phil Berlowitz and Grant McCool)