MOSCOW, Nov 21 (Reuters) - The Russian rouble

strengthened slightly against the U.S. dollar on Thursday but

remained above the 100 mark, the highest level in more than a

year.

At 0900 GMT, the rouble was up 0.1% at 100.50 against

the dollar. The Russian currency was flat at 106.15 to the euro

, according to LSEG data. The rouble was down 0.3%

against the yuan at 13.86 in trade on the Moscow stock exchange.

The rouble's official exchange rate, set by the central

bank, broke through the 100 mark against the U.S. dollar for the

first time since October 2023 this week amid concerns of further

escalation in Russia's standoff with the West.

The rouble has been falling since the start of Ukraine's

incursion into Russia's Kursk region on Aug. 6 and has lost

nearly 19% in value to the dollar since then, based on LSEG

data.

Western sanctions imposed on the Moscow Exchange (MOEX) and

its clearing agent, the National Clearing Centre, on June 12

stopped all trade in dollars and euros at MOEX.

The central bank sets its official dollar rate using

over-the-counter (OTC) trade data from banks. This tends to make

the exchange rate more opaque and volatile. The central bank set

the rouble exchange rate at 100.22 to the dollar.

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

exchange and are a guide for OTC market rates, were up 0.5% at

100.74.

Brent crude oil, a global benchmark for Russia's

main export, was up 0.7% as concerns over escalating tensions

between Russia and Ukraine outweighed the impact of a

bigger-than-expected increase in U.S. crude inventories.