MOSCOW, June 27 (Reuters) - The Russian rouble rose strongly against the dollar on Thursday in volatile, low-liquidity trade, supported by exporters' sales of foreign currency earnings ahead of a tax payment deadline on Friday.

Sanctions on Moscow Exchange and its clearing agent, the National Clearing Centre (NCC), have led to a range of varying prices and spreads as trading shifted to the over-the-counter (OTC) market on June 14, obscuring access to reliable pricing for the Russian currency.

On the interbank market, where liquidity can be low as major Russian banks that have been sanctioned cannot participate, the rouble traded 3.9% higher at 84.80 by 0833 GMT against the dollar.

The average dollar-rouble mixed composite rate, calculated by LSEG and based on data from international brokers and counterparties, stood at 84.16.

Against the yuan, the rouble was 2.3% stronger at 11.43.

The central bank's official dollar-rouble rate was set at 87.81 for June 26, calculated on the basis of OTC trading.

Brent crude oil, a global benchmark for Russia's main export, was up 0.5% at $85.70 a barrel. (Reporting by Mark Trevelyan; Editing by Anil D'Silva)