"A more complex and harmful downside risk is the possibility that potential growth rate is lower than estimated and a smaller output gap than previously estimated," the report said.
In June, the IMF downgraded forecast for the US economy in 2016 to 2.2 percent from 2.4 percent predicted in April.
The slower-than-anticipated growth rate would mean "the US economy could soon bump up against capacity constraints that would slow growth and generate domestic inflationary pressures with negative global spillovers," the report added.
"Given uncertainty surrounding the implications of the UK referendum, continued financial market volatility or a further appreciation of the US dollar are possible," the report said.
The IMF board of Directors urged the US Federal Reserve to keep the pace of interest rate normalization data-dependent and proceed "cautiously" with rate hikes, according to the report.
