Russia's central bank says it is scrapping daily controls on the value of the ruble, allowing the weakening currency to trade freely in financial markets.

The bank said that effective Monday it will stop setting daily limits for the ruble's fluctuations and will not have any obligation to intervene in markets to support the currency, which has lost nearly half its value against the dollar this year.

The bank added it will stand ready to intervene if necessary to fend off "threats to financial stability."

The ruble has nosedived in recent months amid the financial uncertainty created by Western sanctions over the Ukrainian crisis, and, more recently, a plunge in oil prices.