The Organization for Economic Co-operation and Development says economic growth will slow a bit in the industrialized world this year to an annual rate of 2.6 percent.
The OECD's report blames rising energy costs and economic problems in Europe for the slowdown.
The OECD's 30 members include European industrialized nations along with the United States, Japan, and Korea.
Tuesday's report calls prospects for European growth weak and uncertain, and urges economic reforms and cuts in interest rates.
The OECD predicts U.S. economic growth will accelerate slightly to 3.6 percent. The report also warns that the dollar might weaken "abruptly" unless Washington does more to cut its "unsustainable" trade deficit.
The economists say strong East Asian economies have helped boost world trade.