MOSCOW, May 21 (Reuters) - The Russian rouble

strengthened against the U.S. dollar on Tuesday to its strongest

point since early March, supported by high interest rates, state

foreign currency sales and capital controls.

By 0715 GMT, the rouble was 0.5% higher at

90.29 to the dollar after trading in a range of 90.250 to 90.805

and reaching its strongest since March 6.

Against the euro, the rouble rose 0.46%

to 98.17. It also gained 0.43% to 12.45 against the yuan

.

Brent crude oil, a global benchmark for Russia's

main export, fell 0.7% to $83.14 a barrel.

Russian stock indexes fell. The dollar-denominated RTS index

fell 0.03% to 1,203.77. The rouble-based MOEX Russian

index lost 0.53% to 3,449.75.

($1 = 90.2925 roubles)

(Reporting by Reuters)