MOSCOW, Aug 27 (Reuters) - The Russian rouble

strengthened against the U.S. dollar on Tuesday, supported by

foreign currency sales by exporting companies that convert their

earnings into roubles to pay domestic taxes at the end of the

month.

At 0800 GMT, the rouble was 0.5% stronger at 91.80 to

the dollar, according to LSEG data. The rouble fell as much as

9% against the dollar earlier in August after Ukraine's surprise

attack on Russia's Kursk region, before stabilising around

current levels.

"The rouble feels comfortable ahead of the main tax payment

period," said Zenit bank analyst Vladimir Evstifeev.

Trading in major currencies in Russia shifted to the

over-the-counter (OTC) market, obscuring price data, after

Western sanctions on the Moscow Exchange and its clearing agent,

the National Clearing Centre, were introduced on June 12.

According to an analysis of the OTC market, the rouble

weakened by 0.6% to 11.74 against the Chinese yuan, which has

become the most traded foreign currency in Moscow. The rouble

strengthened by 1.4% against the yuan in Monday's session.

The rouble is currently benefiting from high interest rates

after the central bank increased its benchmark rate to 18% in

July.

One-day rouble-dollar futures, which trade on the Moscow

Exchange and are a guide for OTC market rates, were down 0.2% at

90.57.

The central bank's official exchange rate, which it

calculates using OTC data, was set at 91.77 to the dollar.

The rouble was 0.2% stronger at 102.39 against the euro

, according to LSEG data.

Brent crude oil, a global benchmark for Russia's

main export, was down 0.2% at $81.30 a barrel, as prices paused

recent advances after a surge of more than 7% in the previous

three sessions.