Manufacturers in the Plains states reported slightly weaker economic conditions this month, according to a regional Federal Reserve bank report released Thursday. Comments suggest a rising shortage of skilled labor.

The Kansas City Fed's manufacturing composite index slipped to 7 in April after it rebounded to 10 in March from 4 in February. A reading above zero denotes expansion.

On a year-over-year comparison, the April composite index increased to 14 from 12.

"Regional factory expansion was not quite as strong in April as in March, when better weather provided a boost," said Chad Wilkerson, an economist at the Kansas City Fed. "But April's numbers were otherwise the best in nearly two years, and firms were generally optimistic."

The subindexes slowed in April after posting high March numbers that reflected a catch-up in activity after the harsh winter.

The production index fell to 12 in April from a three-year high of 22 in March, but the April reading is far better than the contractionary numbers seen in December and January.

The shipments index declined to 14 from an eight-month high of 16.

The new orders index dropped to 9 after it more than doubled to 13 in March from 5 in February. The backlog index improved to 4 from -1 last month.

The employment index increased to 3 from 0. The workweek index doubled to 6 from 3.

The comments contained in the Kansas City Fed report show some manufacturers in the Plain states are having trouble finding skilled labor. That echoes the results of other surveys.

"We have many available jobs for truck drivers, some production supervisory personnel, and technical/electrical roles. We are challenged finding good people with the right skill sets," said one respondents cited in the report.

Cost pressures also are building. The prices-paid index increased to 21 in April from 16 last month. The prices-received index fell sharply to 2 from 10.

Manufacturers are more upbeat about the next six months.

The composite expectations index jumped to 21 from 11. The future employment index increased to a three-month high of 22 in April from 2 in March.

The Kansas City Fed district includes Colorado, Kansas, Nebraska, Oklahoma, Wyoming, northern New Mexico and western Missouri.

Write to Kathleen Madigan at kathleen.madigan@wsj.com

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