Russia's ruble has dropped more than 3 percent, pressured by declining oil prices and the flagging economy.

The Russian currency traded 52 rubles against the dollar at the opening on Monday after losing 15 percent in the previous week.

The Kremlin, which in the past supported the exchange rate by buying up the rubles, says it considers the pressure on the ruble to be speculative and is happy for a ruble free float.

The ruble has been suffering from low oil prices as well as its flagging economy and the pressure of Western sanctions over its role in Ukraine.

Oil prices, the backbone of the Russian economy, dropped roughly 25 percent since the summer. Brent crude, an international benchmark, fell 3 percent to $70.15 a barrel on Friday.