The United States on Monday urged the Group of 20 economic powers, which holds a meeting later this week, to avoid competitive currency devaluation that would threaten economic growth.
"To ensure growth strategies in the world's largest economies are mutually compatible and promote global growth, the G20 needs to deliver on the commitment to move to market-determined exchange rates and refrain from competitive devaluation," said Lael Brainard, the Treasury official who will lead the US delegation to the meeting.
Japan's recent monetary easing has stoked fears, especially in Europe, of a currency war between the major economies as policymakers seek to devalue their currencies to make exports more competitive.
Brainard, the Treasury under secretary for international affairs, notably called on China to do more to let the yuan float more freely in the market.
"It will be important that China... reinvigorate the move to a market-determined exchange rate and interest rates," she said.
Brainard was speaking at a news conference focused on the G20 finance chiefs meeting that opens Friday in Moscow.
She underscored that some emerging-market economies have tightly run exchange-rate regimes with extensive capital controls.
"The asymmetry in exchange rate policy creates the potential for conflict" and "generates protectionist measures," she noted.
She also called on Beijing to improve its adherence to international trade rules.
The United States regularly accuses China, which had a record $315 billion trade surplus with the US in 2012, of favoring its state-controlled businesses and subsidizing exports.
Saying that global growth was still weak after the 2007-2009 financial crisis, Brainard warned against complacency and recommended avoiding any severe budget adjustments.
"We must avoid jeopardizing the recovery with a premature shift to restraint," she said.
One-third of the G20 advanced and emerging-market economies, which represent almost 90 percent of the global economy, were in recession, she said.
Brainard said that the International Monetary Fund's recent admission that it had underestimated the impact of austerity plans on growth should raise a red flag when policymakers look at making budget cuts.
"The G20 has to do a better job balancing medium-term fiscal consolidation with the imperative of supporting near-term growth," she said.
"We need to do more to get people back to work."
As for the United States, Brainard said that big across-the-board spending cuts due to take effect March 1, known as sequestration, pose a serious threat to the country. Without an agreement in Congress to avert the cuts, the Defense Department budget will be cut by up to 10 percent.
"It's important to avoid sequestration, which is a blunt and indiscriminate instrument that poses a serious threat to national security, domestic priorities and the economy, she said.