* 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

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 .MILA00000CUS 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 .MILA00000PUS rose 5.7% this week.

Brazil's real BRBY BRL= 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 CNYLPR5Y=CFXS 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 COP= 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 MXN= and Chile's peso CLP= 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 EURRUBTN=MCX , 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 .MSCIEF

1033.62

1.85 MSCI LatAm .MILA00000PUS

2376.34

2.24 Brazil Bovespa

.BVSP

108093.13

1.02 Mexico IPC

.MXX

51422.35

0.26 Chile IPSA

.SPIPSA

4997.91

0.32 Argentina MerVal

.MERV

87641.40

-1.12 Colombia COLCAP

.COLCAP

1449.02

2.69

Currencies

Latest

Daily %

change Brazil real

BRBY

4.8647

1.10 Mexico peso

MXN=D2

19.8552

0.34 Chile peso

CLP=CL

836.9

0.00 Colombia peso COP=

3964.95

2.09 Peru sol

PEN=PE

3.728

0.16 Argentina peso (interbank) ARS=RASL

118.4800

-0.11

Argentina peso (parallel) ARSB=

201

2.49

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Rising EM interest rates Link

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Reporting by Anisha Sircar, Bansari Mayur Kamdar and Shreyashi
Sanyal in Bengaluru; Editing by Kirsten Donovan and Matthew
Lewis