NEW YORK (REUTERS) - The U.S. services sector grew at a slower pace for a third straight month in June, as rates of expansion in both new business and hiring eased, an industry report showed on Thursday.

Financial firm Markit said the "flash" or preliminary, reading of its Purchasing Managers Index for the services sector slipped to 54.8 in June, from a final reading of 56.2 in May and short of expectations that called for a 56.7 reading.

A mark above 50 signals expansion in economic activity.

Markit's June reading of new business at service companies fell to 55 from the final reading of 55.7 in May.

Markit's composite PMI, a weighted average of its manufacturing and services indexes, fell to 54.6 in June from 56 in May. Earlier this week, Markit's final read on U.S. manufacturing activity showed slower growth in June. "The latest flash PMI surveys showed the smallest rise in service sector activity since January and the slowest growth of factory output for over a year and a half," Markit chief economist Chris Williamson said in a statement.