Private sector in the U.S. added 173,000 jobs in May, according the ADP report on Thursday. April's figure was revised up to 166,000 jobs from a previous reading of 156,000 jobs.

Analysts expected the private sector to add 175,000 jobs.

Services sector added 175,000 jobs in May, while goods-producing sector shed 1,000.

"Job growth has moderated this spring as energy companies and manufacturers shed jobs," the Chief Economist of Moody's Analytics Mark Zandi said.

"Retailers are also more circumspect in their hiring. Despite the recent slowdown, job growth remains strong enough to reduce underemployment," he added.

Official labour market data will be released on Friday. Analysts expect that U.S. unemployment rate is expected to decline to 4.9% in May from 5.0% in April. The U.S. economy is expected to add 162,000 jobs in May, after adding 160,000 jobs in April.