The Russian ruble slumped to new all-time lows on Thursday as speculative pressure on the currency built, piling pressure on policymakers and reinforcing fears about the fragility of the commodity-dependent economy.

Pushed down by a collapse in global prices of oil that has soured sentiment for Russian assets, the rouble broke through 83 rubles per dollar for the first time before later slumping to 86 per dollar.

The Kremlin said the currency was not collapsing, but at its lowest point on Thursday it was the biggest single-day drop since September last year.

The rouble was showing some signs of stabilization in the early afternoon, having earlier been down as much as 5.3 percent against the dollar.

At 1020 GMT it was trading down 3.1 percent against the dollar at 84.04 and had lost 3.2 percent to 91.59 versus the euro.

Currency dealers and several large banks said the volume of currency-exchange operations by individuals had not increased dramatically in recent days.

Dealers in Moscow characterized the pressure on the rouble as a speculative attack by financial investors.

A Kremlin spokesman said President Vladimir Putin was being informed regularly about rouble moves but he said: “This is far from being a collapse.”

But there was anecdotal evidence of concern among the population about the ruble’s slide.

Holders of dollar mortgages stormed an office of Delta Credit bank in Moscow on Wednesday, demanding that their mortgage agreements be reviewed.

Express-Volga, a bank based in the Russian provincial city of Saratov, said it would limit its operations with foreign currency from Feb. 1 due to market volatility.

“With these rouble and oil moves I’m sure policymakers must now be nervous as to moves to much greater dollarization by the man on the street,” Tim Ash, a Nomura strategist, said in a note.

Brent crude oil was down 0.1 percent on Thursday 13-at $27.9 a barrel, having earlier been down around 2 percent at $27.3.

The global crude benchmark has lost around 25 percent since the start of the year, while the rouble is down around 12 percent versus the dollar.

Rosbank analysts said despite the new lows for the rouble, the central bank was unlikely to actively intervene to defend the currency in the near term.

“The regulator doesn’t see risks for financial stability in current conditions,” they wrote in a note to clients.

The central bank said on Wednesday the ruble’s weakening had an “objective character” and was taking place “smoothly”.

Russia’s major share indexes were mixed on Thursday, following heavy falls on Wednesday, suggesting bearish sentiment was especially pronounced on the currency market.

The dollar-denominated RTS index was down 0.7 percent to 624 points, while the rouble-based MICEX was 2.1 percent higher at 1,665 points.

The RTS hit its lowest since December 2014, when Russian financial markets were also in turmoil and the rouble first collapsed to the level of 80 rubles per dollar.