Markit Economics released its final manufacturing purchasing managers' index (PMI) for the U.S. on Monday. The U.S. final manufacturing purchasing managers' index (PMI) decreased to 50.8 in April from 51.5 in March, in line with the preliminary estimate.

A reading above 50 indicates expansion in economic activity.

The index was driven by a slower pace of growth in output and new business.

"The April PMI data suggest there's no end in sight to the current downturn in manufacturing activity," Markit's Chief Economist Chris Williamson said.

"Rather than reviving after a disappointingly weak first quarter, the data flow therefore appears to be worsening in the second quarter, raising question marks over whether GDP growth will improve on the near-stalling seen in the first three months of the year," he added.