MOSCOW: The rouble slumped on Monday, dragged down by weak oil prices and as investors weighed the risk of new sanctions against Moscow as Kremlin critic Alexei Navalny was remanded in pre-trial detention a day after his return to Russia.

By 1428 GMT, the rouble was 0.7% weaker against the dollar at 74.19, at one point losing 1% on the day and slipping to a near one-week low.

The rouble had lost 0.7% to trade at 89.51 versus the euro.

The next rate-setting meeting is scheduled for Feb. 12.

Russian stock indexes were mixed.

The dollar-denominated RTS index was down 0.3% at 1,469.2 points. The rouble-based MOEX Russian index was up 0.3% at 3,460.1 points.

Western nations were quick to call for Navalny’s release after police detained him on Sunday when he flew home from Germany for the first time since he was poisoned last summer, pressuring Russian assets. On Monday, a Russian judge ruled that Navalny should be held in custody for 30 days until Feb. 15, a decision which was largely ignored by the rouble, which was already falling on the day.