WASHINGTON (Reuters) -U.S. private payrolls unexpectedly fell in June and job gains in the prior month were smaller than initially thought, the ADP National Employment Report showed on Wednesday.

Private payrolls dropped by 33,000 jobs last month after a downwardly revised 29,000 increase in May. Economists polled by Reuters had forecast private employment increasing 95,000 following a previously reported gain of 37,000 in May.

The ADP report, jointly developed with the Stanford Digital Economy Lab, was published ahead of the more comprehensive employment report for June due to be released on Thursday by the Labor Department's Bureau of Labor Statistics. There is no correlation between the ADP and BLS employment reports.

The BLS' employment report is being published a day early because of the Independence Day holiday on Friday. 

Job growth has ebbed as businesses grapple with trade policy uncertainty, but companies have not yet resorted to widespread layoffs, keeping the labor market anchored.

A separate report from global outplacement firm Challenger, Gray & Christmas showed job cuts announced by U.S.-based employers dropped 49% to 47,999 in June.

Planned layoffs totaled 247,256 in the second quarter, down 50% from the January-March quarter. Hiring plans, however, dropped to 3,191 last month from 9,683 in May.

Sluggish hiring was also evident in the government's Job Openings and Labor Turnover Survey, or JOLTS report on Tuesday, which showed a 112,000 decline in hires to 5.503 million in May. The JOLTS report also showed there were 1.07 job openings for every unemployed person in May, up from 1.03 in April.

"Without a strong economic driver, hiring may remain measured through the rest of the year," said Andrew Challenger, senior vice president at Challenger, Gray & Christmas.

Economists polled by Reuters expect the government's employment report to show private payrolls increased by 105,000 in June after rising 140,000 in May.

Overall nonfarm payrolls are estimated to have advanced by 110,000 jobs after gaining 139,000 in May. The unemployment rate is forecast climbing to 4.3% from 4.2% in May.