Washington ? Surging gasoline prices helped trigger another big increase in consumer inflation in May, and one closely watched price gauge rose at the fastest pace in 11 years.

The Labor Department reported Wednesday that its Consumer Price Index rose 0.4 percent last month, in line with expectations, while core inflation, which excludes food and energy, was up a worse-than-expected 0.3 percent.

Private economists said the latest news on inflation virtually guaranteed a 17th straight interest rate increase by the Federal Reserve at the end of this month.

All energy prices were up 2.4 percent in May and have risen at an annual rate of 30.8 percent through May, nearly double the 17.1 percent rise for all of last year.

Excluding energy and food, core inflation was up 0.3 percent. That marked the third straight 0.3 percent monthly gain and translated into an annualized increase of 3.8 percent over the past three months, the fastest pace since 1995.