MOSCOW: The rouble opened slightly weaker against the US dollar in thin trade on Saturday, the last trading day of the year for the Russian currency, holding near its lowest levels in more than 3 months amid weak oil prices.

At 0725 GMT, the rouble was 0.1 percent weaker against the dollar at 69.50 and was flat versus the euro at 79.50.

Brent crude oil, a global benchmark for Russia's main export, plunged in December to its lowest in more than a year because of supply glut fears, sending the rouble to its weakest since mid-September.

Activity on the Russian market is expected to remain low until Jan. 9, when Russian holidays end. The Moscow Exchange will be closed from Dec. 30 to Jan. 2 and on Jan. 5-7.

Russian stock indexes were up on Saturday following a rally on the Wall Street. The dollar-denominated RTS index adding 0.4 percent to 1,070 points. The rouble-based MOEX Russian index was 0.16 percent higher at 2,362 points.