MOSCOW, April 15 (Reuters) - The Russian rouble slightly

weakened against the U.S. dollar on Monday.

By 0715 GMT, the rouble was 0.18% lower at

93.60 to the dollar after trading in a range of 93.328 to

93.640.

Against the euro, the rouble fell 0.2% to

99.81, and it dropped 0.25% to 12.89 against the yuan

.

Brent crude oil, a global benchmark for Russia's

main export, fell 0.8% to $89.68 a barrel.

Russian stock indexes were mixed. The dollar-denominated RTS

index fell 0.12% to 1,164.02. The rouble-based MOEX

Russian index gained 0.07% to 3,458.55.

($1 = 93.6025 roubles)