MOSCOW, June 18 (Reuters) - The Russian rouble strengthened in the over-the-counter (OTC) and the interbank market on Tuesday, in trading now characterised by wide spreads after new U.S. sanctions that forced Russia's leading exchange to halt dollar and euro trading last week.

The sanctions on Moscow Exchange and its clearing agent, the National Clearing Centre (NCC), ultimately led to a range of varying prices and spreads as trading moved OTC on June 14, obscuring access to reliable pricing for the Russian currency.

The rouble was 1.2% higher at 85.94 by 0759 GMT, according to a Reuters analysis of the OTC market. The euro was up 1.3% at 92.15.

The restrictions on dollar and euro trading have provoked sales of foreign currency for roubles, boosting the Russian currency, which is also buttressed by capital controls, interest rates at 16% and Russia's strong current account surplus.

The yuan, which was already the most traded currency with the rouble in Moscow, firmed 1.2% to 11.81.

An indication of the wide spreads, the difference between buying and selling prices, available was the central bank's official dollar-rouble rate set at 89.05 for Tuesday, calculated based on OTC trading.

On the interbank market, where liquidity can be low and major Russian banks that have been sanctioned by the United States cannot participate, the rouble traded at 87.20 against the dollar.

Brent crude oil, a global benchmark for Russia's main export, was down 0.1% at $84.15 a barrel. (Reporting by Alexander Marrow; Editing by Shinjini Ganguli)