The International Monetary Fund looks likely to cut its forecast for global growth next month when it updates its projections for the world economy.
IMF head Christine Lagarde said in a speech that global growth would "likely be a bit weaker" than anticipated, the BBC reports.
Problems in the euro zone and worries about the US economy continued to weigh on investors' confidence, she said.
She also warned of a slowdown in some of the emerging nations that previously bolstered global economic growth.
In July, the IMF cut its global growth projection for 2013 to 3.9%, but left its 2012 forecast unchanged at 3.5%.
Mrs Lagarde, speaking in Washington on Monday, welcomed recent measures by euro zone governments and the European Central Bank to get a grip on the bloc's problems.
