MOSCOW, July 9 (Reuters) - The Russian rouble weakened against the dollar on Tuesday, pressured by reduced foreign currency inflows from exporters at the start of the month and lower FX sales from the Russian state in July.

Sanctions on Moscow Exchange and its clearing agent, the National Clearing Centre (NCC), 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.

The rouble has also become more volatile in lower-volume trade, making sharp swings quite common.

Against the yuan, which had already become the most traded foreign currency in Moscow before the latest sanctions were imposed, the rouble shed 0.6% to 11.96, according to analysis of the OTC market.

It was down 1.6% at 95.29 against the euro.

The rouble has lost support from month-end tax payments that usually require exporters to convert foreign currency to meet local liabilities.

Reduced FX sales by the central bank in the second half of the year and increased purchases by the finance ministry in July have also reduced the rouble's propensity to strengthen.

High oil prices, capital controls and high interest rates helped to lift the rouble to one-year highs in June. The central bank has signalled that an increase to interest rates from 16% is highly likely when it next meets on July 26.

Analysts polled by Reuters expect the bank to increase its key rate to 18%.

"Fundamentally, the rouble looks very strong," said Alor Broker's Alexei Antonov. "High interest rates will stimulate everyone, including exporters, to invest in rouble instruments."

Brent crude oil, a global benchmark for Russia's main export, was down 0.3% at $85.50 a barrel.

(Reporting by Alexander Marrow Editing by David Goodman)