Markit Economics released its final manufacturing purchasing managers' index (PMI) for the U.S. on Wednesday. The U.S. final manufacturing purchasing managers' index (PMI) fell to 53.6 in June from 54.0 in May, beating the previous estimate of a decline to 53.4. It was the lowest level since October 2013.

A reading above 50 indicates expansion in economic activity.

The Markit Chief Economist Chris Williamson said that the reading suggests the U.S. economy was slowing again.

"The slowdown is largely linked to a third consecutive monthly fall in exports, in turn attributed by many companies to the strong dollar undermining international competitiveness," he added.