People browse booths at a military veterans' job fair in Carson, California October 3, 2014. REUTERS/Lucy Nicholson

WASHINGTON (Reuters) - The pace of hiring by U.S. employers slowed to near a two-year low in April, pushing up job openings in a potential sign that firms are having a hard time finding workers.

The Labor Department said on Wednesday in its monthly Job Openings and Labor Turnover Survey, or JOLTS, that the rate of hiring fell to 3.5 percent from 3.7 percent in March. That was the slowest rate since August 2014.

Job openings, a measure of labor demand, increased 118,000 to a seasonally adjusted 5.79 million, the highest number since last July. The job openings rate rose to 3.9 percent.