The core inflation rate, which excludes volatile food and energy prices, accelerated to 2.2 percent in the year ended in April.
The core index, which excludes food and energy prices, declined 0.1 percent, compared with a forecast of a 0.2 percent increase.
But the core rate, which excludes the volatile energy and food prices, increased three-tenths of 1 percent, the largest climb since September.
But the so-called core rate, which excludes food and energy prices, rose 0.3 percent, compared with 0.1 percent increases the previous two months.
The report showed that the core producer price index for finished goods, which excludes food and energy prices, was unchanged.
The so-called core index, which excludes volatile food and energy prices, rose 0.7 percent.
The core inflation rate, which excludes food and energy prices, rose only one-tenth of 1 percent.
The core rate, which excludes food and energy prices, was up one-tenth of a percent.
The index, which excludes volatile food and energy prices, registered an increase of just 0.1 percent in July, the smallest this year.
But after excluding two volatile components, energy and food prices, the so-called core inflation rate rose 0.2 percent, the smallest increase in five months.