* EM shares index extends losses to day 6, EM FX at one-month low

* Fed Chair Powell's testimony to Congress on deck

* Belarusian bonds, FX stabilize after slide

* Hungarian central bank decision due later

June 22 (Reuters) - Emerging market assets rose briefly but then extended losses for a sixth day in a row on Tuesday as investors looked to more monetary policy hints from the United States, while Belarusian government bonds and the currency stabilized after steep losses.

MSCI's index of EM shares inched lower after a bruising five days when it lost over 2%, while a currency equivalent stayed at one-month lows.

U.S. Fed Chair Jerome Powell's testimony to Congress on Tuesday will be a focus for markets after his prepared comments said the U.S. economy continues to show "sustained improvement", but that inflation was a concern.

Analysts at Maybank said that markets would welcome some reassurance from the Fed that a tightening cycle will not start sooner than planned, as suggested by some Fed members.

The Belarusian rouble was mostly flat while yields on dollar bonds came off highs hit on Monday when the West imposed new sanctions on Belarus over the forced landing of a passenger flight to detain a dissident journalist.

Russian ties with some world powers also came under pressure after the European Union included Russian businessman Mikhail Gutseriyev, the largest single foreign investor in Belarus, in its sanctions.

Separately, the Kremlin on Monday said it did not expect the United States to stop trying to "contain" Russia amid talk of new U.S. sanctions on Moscow over the alleged poisoning if a Kremlin critic.

The Russian rouble made lazy gains against a stronger dollar, staying just over 2% off this year's highs.

The South African rand fell 0.2% after a 1% rally last session when it was one of the rare gainers against the dollar, while the lira pulled up xx% from all-time lows hit on Monday.

Hungary's forint edged lower against the euro with all eyes on a central bank meeting later in the day. A 25 basis point hike is expected, making it the first European Union central bank to tighten policy since the coronavirus pandemic.

For GRAPHIC on emerging market FX performance in 2021, see http://tmsnrt.rs/2egbfVh For GRAPHIC on MSCI emerging index performance in 2021, see https://tmsnrt.rs/2OusNdX

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For RUSSIAN market report, see (Reporting by Susan Mathew in Bengaluru; Editing by Raissa Kasolowsky)