Russia on Wednesday pledged to cut the share of U.S. treasuries in its $400 billion reserves, driving the dollar lower on global markets, although it said the move would be gradual and only replace bonds as they expire.

Central Bank First Deputy Chairman Alexei Ulyukayev said it would buy bonds issued by the International Monetary Fund and also up the share of reserves held in foreign bank deposits, also reduced in the wake of the banking crisis last year.

Russia holds about 30 percent of its reserves in treasuries after Central Bank asset managers last year cut their holdings of riskier assets such as bonds of U.S. agencies Fannie Mae and Freddie Mac.

"Now this share [of treasuries] will fall because the window of opportunity is opening, the situation with banks is becoming clearer," Ulyukayev said. "We will increase the share of bank deposits, the share of repos will be bigger as well."

He said Russia would not immediately sell its treasury holdings but would rather wait until the securities mature, gradually replacing them with other assets. Russian officials earlier said they were concerned about U.S. inflation.

Russia earlier pledged to buy about $10 billion worth of bonds to be issued by the IMF as part of a fundraising effort to help countries hit by the global financial crisis, but there is no firm timetable for such an issue.

Russia increased its investment in liquid treasuries during the peak months of the crisis to have the money readily available to support the ruble and is ready to retrace those moves now that the pressure on the ruble has eased.

The country keeps most of its sovereign debt holdings in short-term paper. It took the country less than a year to cut its position in papers of Fannie and Freddie from $100 billion to virtually zero.

The dollar slipped against a range of currencies, while U.S. Treasury yields rose after news of the Russian statement. The dollar index fell as low as about 79.48 after the news from 79.66 shortly before the comments.

U.S. Treasuries fell further after the comments, pushing up the benchmark 10-year T-note yield more than 5 basis points to a session high of 3.92 percent.

"This is potentially quite negative for the dollar," said Geoff Kendrick, senior currency strategist at UBS in London.

"The main jump was in sterling. … If anyone just now would benefit, it would probably be investments into sterling as a reserve currency."

Russia, the world's second-largest oil exporter, has been pushing for a rethink on the dollar's status as the world's reserve currency of choice and plans to discuss the dollar's role with BRIC group partners Brazil, India and China at a summit next week.

Ulyukayev said Russia could also consider including assets denominated in China's yuan but only after Beijing liberalizes its capital account transactions, making the yuan a convertible currency.