Treasury Secretary Jacob Lew said Tuesday that the U.S. economy is strengthening, but he is concerned that other nations are not doing their part to boost global growth.

The United States took decisive steps after the 2008 financial crisis to get its economy growing, he said. In contrast, he described a less determined response by other nations to their own economic problems.

Lew stressed a “need for more action in quite a number of parts of the world,” although he didn’t single out specific countries.

“I don’t think the United States alone can pull the global economy to where it needs to be,” Lew said during an appearance at the Peterson Institute to preview this weekend’s meetings of the 188-nation International Monetary Fund and its sister lending agency, the World Bank.

The IMF on Tuesday trimmed its outlook for global growth, reflecting weaker expansions in Europe, Japan and Latin America. It also warned that the United States, Europe and Japan could face years of sluggish growth unless government took steps to accelerate activity.

The U.S. dollar has been strengthening in recent weeks, a development that could harm U.S. growth prospects by making its products less competitive in global markets. At the same time, declines in the value of other global currencies such as the Japanese yen and euro could boost exports in those regions.

“We have called on many countries in the world to take decisive action to get their economies to grow,” Lew said in response to a question about whether he had concerns over a strengthening dollar.

Asked specifically about China, Lew said the administration still believed that China’s currency was undervalued in relation to the dollar and needed to strengthen further. He said the Chinese government needed to stop intervening in currency markets on a routine basis to lower the value of the yuan.

(AP)