At 0735 GMT, the rouble was slightly weaker against the dollar at 66.49 and remained unchanged at 75.55 versus the euro.

The Russian central bank said on Thursday it had resumed forex purchases on January 15 after a five-month hiatus. It said foreign currency worth 15.6 billion roubles had been purchased on that day.

The Russian central bank had halted forex purchases in August when the rouble was especially volatile.

These operations, which restore daily downside pressure on the rouble, are not expected to disrupt the market balance, according to Alexei Zabotkin, head of the central bank's monetary policy department.

Many emerging market currencies edged down on Thursday, reflecting uncertainty over China's economic growth outlook and reminders of discord in Sino-U.S relations.

Brent crude oil, a global benchmark for Russia's main export, was down 0.4 percent at $61.09 a barrel, dipping slightly as U.S. crude production quickly approached an unprecedented 12 million barrels per day (bpd).

Russian stock indexes were slightly up.

The dollar-denominated RTS index was up 0.3 percent to 1,156.46 points. The rouble-based MOEX Russian index was 0.1 percent lower at 2,437.36 points.

Moscow-traded shares in Rusal were up 4 percent after a bid to keep U.S. sanctions on companies linked to Russian oligarch Oleg Deripaska, including aluminium firm Rusal, failed in the senate..