U.S. job openings fell almost across the board in July, according to a government report on Tuesday that shined a light on labor market weakness during that month.

Job openings - a measure of labor demand - fell 180,000 to a seasonally adjusted 3.7 million, the Labor Department said in its monthly Job Openings and Labor Turnover Survey.

The declines were nearly broad-based, with sizeable drops in trade, transportation and utilities, professional and business services, and health care and social assistance. There were modest gains in leisure and hospitality, and manufacturing.

The report could explain the surprise slowdown in nonfarm payroll growth during that month. Employers added only 104,000 new jobs to their payrolls in July, the fewest since June 2012.

While hiring regained some momentum in August, the increase was below market expectations and suggested a moderation in the job growth trend from earlier in the year.

(Reporting by Lucia Mutikani; Editing by Andrea Ricci)