U.S. factories expanded in April at the same pace as in March, but manufacturers are starting to curtail hiring in a possible sign of weakness.

The Institute for Supply Management, a trade group of purchasing managers, says its manufacturing index was unchanged at 51.5.

The index had dropped in the prior five months. Still, any reading above 50 signals expansion.

U.S. manufacturers have faced a drag in recent months from falling oil prices and a rising dollar.

New orders and productivity improved in April, but the hiring component of the index slipped below 50 to 48.3, suggesting the possibility of layoffs and less hiring.