* Brazil"s real set for weekly losses as political tensions weigh * Limited upside seen for Mexico"s peso - analyst * Chile"s peso drops on Escondida strike plan * JBS, Lojas Americanas rally By Susan Mathew Aug 6 (Reuters) - Latin American currencies hit session lows on Friday as the dollar rallied after strong jobs data from the United States spurred bets that the U.S. Federal Reserve might bring forward its timeline for tapering stimulus. But Brazil"s real fell 0.7% in a volatile session also hampered by political tensions ahead of elections next year. The currency is set to mark its third straight week in the red. A Brazilian congressional committee on Thursday voted against a constitutional amendment to adopt printed ballots, in a major defeat for far-right President Jair Bolsonaro, whose popularity has taken a dive. "The domestic political turbulence combined with a resurgence of concerns about the spending cap create conditions in which the currency will benefit only to a limited extent from (a hawkish) central bank," Commerzbank analysts warned. The Mexican peso was steady, but was set to end the week marginally lower. "With increasing (coronavirus) infection figures, concerns are likely to grow in the future that renewed restrictions could slow down the economic recovery (in Mexico) and thus also the central bank"s actions," Commerzbank said. "Against this backdrop and in view of global risks, we continue to see only limited MXN recovery potential." As the dollar rallied, Chile"s peso dropped 0.4%. The union representing workers at Chile"s Escondida copper mine, the world"s largest, on Thursday instructed its members to prepare for a strike due to slow progress in contract talks being mediated by the government. The currency is down almost 3% for the week, its worst in seven weeks. Among stocks, Brazilian retailer Lojas Americanas looked to snap a three-day winning streak after it said it had "preliminary contact" with apparel retailer Marisa Lojas , spurring bets for an offer. Meatpacker JBS jumped more than 2% on its deal to buy Australian fish farmer Huon Aquaculture Group in an all-cash deal for A$425 million ($314.12 million). In bonds, JPMorgan has turned net bullish on hard-currency emerging market sovereign and semi-sovereign debt by going overweight on the EMBI Global Diversified index, the investment bank said. Key Latin American stock indexes and currencies at 1351 GMT: Stock indexes Latest Daily % change MSCI Emerging Markets 1292.17 -0.61 MSCI LatAm 2479.58 -1.35 Brazil Bovespa 121904.21 0.22 Mexico IPC 51189.04 0.11 Chile IPSA 4255.90 0.36 Argentina MerVal - - Colombia COLCAP 1231.34 0.33 Currencies Latest Daily % change Brazil real 5.2499 -0.65 Mexico peso 19.9565 -0.21 Chile peso 780.7 -0.49 Colombia peso 3918.81 -0.12 Peru sol 4.0682 -0.13 Argentina peso 96.9000 -0.01 (interbank) (Reporting by Susan Mathew in Bengaluru; editing by Jonathan Oatis) Our Standards: The Thomson Reuters Trust Principles.