EMERGING MARKETS-Latam FX clocks best week in nearly two months, Brazil leads

* MSCI Latam stocks ~6%, FX 3.6% stronger on the week * Colombian leftist Petro holds lead in presidential race - poll * Rouble hits seven-year high vs euro on capital controls (Adds analyst comments, market details, updates prices) By Anisha Sircar and Shreyashi Sanyal May 20 (Reuters) - A gauge for Latin American currencies logged its biggest weekly gain in about two months on Friday, with Brazil's real at the helm after a bruising week for the dollar, while stocks across the region hit three-week highs on news of stimulus in China. The MSCI's index for Latin American FX jumped 3.6% for the week, its first weekly rise in five weeks and best performance since late March as the greenback lost some shine through the week following a month-long rally. The MSCI's index of Latam stocks rose 5.7% this week. Brazil's real firmed to 4.8 to the dollar, registering weekly gains of 3.7% supported by a steady rise in commodity prices as well as talk of more monetary policy tightening. Buoying most currencies and stocks in the region was news that China lowered the five-year loan prime rate by 15 basis points to 4.45%, while its securities regulator announced measures to support virus-hit sectors via capital markets, easing some fears around the impact of lockdowns and an economic slowdown. "The fact that China is stepping up is a major boost for any Latin American country because their economies are going to be based off of the idea that the globalised system is revised," said Juan Perez, director of trading at Monex. Emerging markets, especially those in resource-rich Latin America, are heavily dependent on China for its demand for raw materials, industrial metals and other commodities. Colombia's peso jumped 1.6%, clocking its best week in over 17 months. Leftist presidential candidate Gustavo Petro, a former guerrilla, held a big lead ahead of the country's May 29 vote, a poll showed, though support for center-right rival Federico Gutierrez ticked up. Mexico's peso and Chile's peso added weekly gains of 1% and 2.7%, respectively. Chile's currency has risen nearly 3% since the country's central bank hiked interest rates by 125 points to 8.25% earlier this month. The country is also amidst a political upheaval that has resulted in the drafting of a brand new constitution "Some of the doubts over Chile's political system have eased after the Constitutional Convention completed a draft of the new charter," said William Jackson, chief emerging markets economist at Capital Economics. "But political risks remain high for now, which may keep the Chilean peso on the back foot in the coming months." Elsewhere, Russia's rouble hit a seven-year high against the euro, which analysts attribute to EU countries preparing to pay Russia for gas and capital controls imposed by Moscow. Meanwhile, Turkey's central bank is likely to hold its policy rate at 14% next week despite an expected further rise in inflation after it hit 70% last month, a Reuters poll showed. Key Latin American stock indexes and currencies at 1946 GMT: Stock indexes Latest Daily % change MSCI Emerging Markets 1033.62 1.85 MSCI LatAm 2376.34 2.24 Brazil Bovespa 108093.13 1.02 Mexico IPC 51422.35 0.26 Chile IPSA 4997.91 0.32 Argentina MerVal 87641.40 -1.12 Colombia COLCAP 1449.02 2.69 Currencies Latest Daily % change Brazil real 4.8647 1.10 Mexico peso 19.8552 0.34 Chile peso 836.9 0.00 Colombia peso 3964.95 2.09 Peru sol 3.728 0.16 Argentina peso (interbank) 118.4800 -0.11 Argentina peso (parallel) 201 2.49 (Reporting by Anisha Sircar, Bansari Mayur Kamdar and Shreyashi Sanyal in Bengaluru; Editing by Kirsten Donovan and Matthew Lewis)