A slow recovery among nations using the euro is holding back the global economy, the Organisation for Economic Co-operation and Development has said.
The market economy group downgraded its growth forecast for most big economies.
Conflicts in Ukraine and the Middle East and the referendum on an independent Scotland are areas of risk and uncertainty, it said.
Its 2014 estimate is a 0.8% increase in the eurozone economy for 2014, compared with a forecast of 1.2% made in May.
The UK’s forecast was cut by 0.1 percentage points to 3.1%.
US economic expansion for 2014 was cut to 2.1% from 2.6%. Japan’s forecast was cut to 0.9% from 1.2%.
The OECD did not provide an update to its forecast for global growth for 2014, which it forecast at 3.4% in May.
“Continued slow growth in the euro area is the most worrying feature of the projections,” the OECD said.
Among countries which are not OECD members, China’s forecast was unchanged at 7.4%. The OECD said China “has so far managed to achieve an orderly growth slowdown to more sustainable rates”.
India was the only economy to be judged by the organisation as likely to grow quicker, with its forecast upgraded to 5.7% from 4.9% after voting in a new government that said it would pursue growth-oriented reforms and progress in containing inflation.