WASHINGTON—U.S. inflation picked up last month as gas prices rose sharply, though price gains for other items were more muted.The consumer price index rose 0.4% in December from November and finished the year up 2.

Wednesday’s report from the Labor Department showed that the consumer price index rose 2.9 percent in December from a year ago, the highest since July.

U.S. producer prices rose less than expected in December as higher costs for goods were partially offset by stable services prices, suggesting inflation remained on a downward trend after progress had stalled in recent months.

The Consumer Price Index ticked up by 0.4% in December, but a measure that excludes food and energy prices slowed for the first time in four months, the Labor Department said on Wednesday. Why it matters: Inflation resumed a cooling trend after a months-long interruption,