Private sector in the U.S. added 156,000 jobs in April, according the ADP report on Wednesday. March's figure was revised down to 194,000 jobs from a previous reading of 200,000 jobs.

Analysts expected the private sector to add 196,000 jobs.

Services sector added 166,000 jobs in April, while goods-producing sector shed 11,000.

"The job market appears to have stumbled in April. Job growth noticeably slowed, with some weakness across most sectors," the Chief Economist of Moody's Analytics Mark Zandi said.

"One month does not make a trend, but this bears close watching as the financial market turmoil earlier in the year may have done some damage to business hiring," he added.

Official labour market data will be released on Friday. Analysts expect that U.S. unemployment rate is expected to remain unchanged at 5.0% in April. The U.S. economy is expected to add 200,000 jobs in April, after adding 215,000 jobs in March.