* Some deals with Ukraine close to being agreed - Lavrov

* Rouble plumbs consecutive lows as default risks mount

* FOMC at 1800 GMT

* MSCIEF headed for best day in two years

* China pledges stimulus measures

March 16 (Reuters) - Most emerging market stocks rose on Wednesday, buoyed by China's pledge to roll out stimulus measures and on hopes of progress in Russia-Ukraine peace talks, though jitters around inflationary pressures and the U.S. Federal Reserve's rate verdict lingered.

MSCI's EM stocks index firmed 4% and was headed for its best day since March 2020, while China stocks also surged about 4% after Chinese Vice Premier Liu He said Beijing will roll out policy steps favourable for its capital markets.

Aiding sentiment, Russian Foreign Minister Sergei Lavrov said some formulations for pacts with Ukraine were close to being agreed. The comments followed Ukrainian President Volodymyr Zelenskiy saying peace talks were sounding more "realistic".

MSCI's EM currencies index strengthened 0.3%, while the Polish zloty and the Czech crown were 0.1% and 0.7% stronger against the euro.

"Sentiment improved following China's pledge to boost financial markets and its economy, and we've heard Lavrov saying there's hope for agreement in Ukraine talks ... there is definitely optimism today, and hopes that a ceasefire will be announced," said Piotr Matys, senior FX analyst at In Touch Capital Markets.

The rouble edged higher in Moscow trade on hopes of peace talks and as markets focused on whether Russia would manage to pay coupons on sovereign debt due later in the day.

However, "economic activity is likely to lose momentum across EMs ... due to high inflation for a longer period than expected before the war began," said Piotr Matys, senior FX analyst at In Touch Capital Markets.

The MSCI EM stocks benchmark has lost 12% this month, and 15% since the onset of the war, driven by risk aversion tied to fears surrounding global stagflation, the fallout from Russia's invasion of Ukraine in late February, and a tighter monetary policy environment in the developed world.

Investor focus was on the U.S. Fed, which is expected to raise rates for the first time in three years and give guidance on future tightening, potentially closing the door on its ultra-easy pandemic-era monetary policy.

"Ordinarily, given the strength of inflationary pressures, a 50 bps hike could be justified - but the volatility in the global environment ... point to the FOMC (the Federal Open Market Committee) treading a more cautious path, but with the caveat that a faster pace of smaller rises could be seen," said Stuart Cole, head macro economist at Equiti Capital.

Money markets are fully priced for a rate hike of at least 25 basis points.

The Turkish lira slipped 0.2% against the dollar, while the South African rand was up 0.2%.

For GRAPHIC on emerging market FX performance in 2022, see http://tmsnrt.rs/2egbfVh For GRAPHIC on MSCI emerging index performance in 2022, see https://tmsnrt.rs/2OusNdX

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For RUSSIAN market report, see (Reporting by Anisha Sircar in Bengaluru; Editing by Maju Samuel)