WASHINGTON (Reuters) -U.S. import prices unexpectedly rose in August, boosted by strong increases in the costs of capital and consumer goods, suggesting domestic inflation was poised to accelerate in the coming months.

Import prices increased 0.3% last month after a downwardly revised 0.2% rebound in July, the Labor Department's Bureau of Labor Statistics said on Tuesday. Economists polled by Reuters had forecast import prices, which exclude tariffs, would dip 0.1% after a previously reported 0.4% advance in July.

Though import prices do not include tariffs, the higher readings suggested exporting countries were not paying for President Donald Trump's sweeping duties on foreign merchandise. 

In the 12 months through August, import prices were unchanged after declining for three straight months. 

Government data last week showed a decline in monthly producer prices in August amid a compression in trade services margins, indicating that domestic firms were probably absorbing some of the tariffs. That data helps to explain why tariffs have not significantly boosted inflation. That process is, however, unfolding as consumer prices picked up in August.

The Federal Reserve is expected to deliver a quarter-percentage-point interest rate cut on Wednesday to aid a struggling labor market. 

Imported fuel prices fell 0.8% in August after increasing 2.5% in July. Food prices dropped 2.1%.

Excluding fuels and food, import prices increased 0.5%. Core import prices were unchanged in July. In the 12 months through August, they increased 1.0%. 

Those readings partly reflect dollar weakness against the currencies of the main U.S. trade partners. The trade-weighted dollar is down about 6.9% this year. 

Prices for imported consumer goods excluding motor vehicles jumped 0.7% last month after falling 0.2% in July. Imported capital goods prices increased 0.5% while those for motor vehicles, parts and engines rose 0.2%.