China and Germany, the world's second-largest and fourth-largest economies respectively, expressed concern about Federal Reserve plans to pump $600 billion into the U.S. economy.
The Fed announced plans to buy $600 billion of assets earlier this week. The Fed hopes that the move, known as quantitative easing, will help boost the U.S. economy and lower unemployment.
German Finance Minister Wolfgang Schaeuble said quantitative easing would not solve the problems in the U.S. economy, but would create "extra problems for the world," BBC News said.
China's Central Bank chief Zhou Xiaochuan said the U.S. should focus on "reforming the international currency system."
Quantitative easing could lead to a weaker dollar, which would make U.S. goods more competitive against those of major global exporters such as China and Germany.
"If the domestic policy is optimal policy for the United States alone, but at the same time it is not an optimal policy for he world, it may bring a lot of negative impact to the world," Zhou said.
The U.S. and China have been at loggerheads for months over the value of China's yuan currency. The U.S. says that China should let the yuan strengthen more.