The Fed is widely expected to cut interest rates next week by a quarter of a percentage point.
The new data is unlikely to derail those forecasts but the uptick in inflation is poised to keep policymakers cautious as they weigh rate cuts in the months ahead.
“President Donald Trump’s inflationary policies – tariffs and restrictive immigration measures – are gradually showing up in the hard data and continue to erode consumers’ purchasing power,” said Atakan Bakiskan, US economist at banking group Berenberg.
Trump has dismissed concerns that his policies will drive up prices or weigh on the economy.
Since Trump latest tariffs took effect last month, most goods entering the US face taxes of between 10% and 50%, depending on their origin.
The price of tariff-sensitive products – such as clothing and household goods – inched up last month in a sign that more businesses might be passing on costs to consumers.
Economists noted that the uptick in food prices, which tend to be volatile, might also be driven in part by Trump administration policies, including tariffs and mass deportations.
Inflation data showed that tomato prices rose by 4.5% in August.
About 70% of tomatoes consumed in the US are imported from Mexico, according to the Florida Tomato Exchange.
In July, the US imposed a 17% tariff on most tomatoes bought in from its southern neighbour.
As well as inflation, the Fed has become increasingly focused on job market weakness.