The International Monetary Fund (IMF) has lowered its forecasts for US and UK economic growth this year, following "weaker-than-expected activity" in the first three months, BBC reports.
The IMF says it now expects the UK to grow by 1.7% this year, compared with the 2% it was previously forecasting.
The US will now grow 2.1%, as against the 2.3% it was predicting in April.
Its prediction that the global economy will grow by 3.5% in 2017, and 3.6% in 2018, is unchanged.
In its latest World Economic Outlook, the IMF said the "pick-up in global growth" that it had anticipated in its previous survey in April "remains on track".
However, it added: "The unchanged global growth projections mask somewhat different contributions at the country level."
A UK Treasury spokesperson said the IMF forecast underlined why the government's plans to increase productivity and get "the very best deal with the EU" after Brexit were "vitally important".
"Employment is at a record high and the deficit is down by three quarters, showing that the fundamentals of our economy are strong," they added.
The UK growth forecast for 2018 remains unchanged at 1.5%, but US growth for next year is now predicted to come in at 2.1%, instead of the 2.5% previously forecast.
"While the markdown in the [US] 2017 forecast reflects in part the weak growth outturn in the first quarter of the year, the major factor behind the growth revision, especially for 2018, is the assumption that fiscal policy will be less expansionary than previously assumed, given the uncertainty about the timing and nature of US fiscal policy changes," the IMF said.
"Market expectations of fiscal stimulus have also receded."