The Russian rouble weakened slightly against China's yuan and was flat against the U.S. dollar in thin trade on Friday.

At 1100 GMT, the rouble was flat at 97.40 against the dollar. It weakened 0.2% to 13.55 against the yuan, according to LSEG data. The rouble weakened by 0.4% to 106.40 against the euro.

Brent crude oil, a global benchmark for Russia's main export, rose more than 2% to $74.53 a barrel after reports that Iran was preparing a retaliatory strike on Israel.

Western sanctions imposed on the Moscow Stock Exchange (MOEX) and its clearing agent, the National Clearing Centre, on June 12 stopped all trade in dollars and euros at MOEX, making the yuan the most-traded foreign currency in Russia.

Trade in dollars and euros has shifted to the over-the-counter (OTC) market, obscuring price data.

One-day rouble-dollar futures, which trade on the Moscow exchange and are a guide for OTC market rates, were up 0.8% at 97.51. The central bank's official exchange rate, which it calculates using OTC data, was set at 97.02 to the dollar.

(Reporting by Gleb Bryanski Editing by Ros Russell)