UPDATE 1-U.S. services growth hits 3-year low in July -ISM

(Adds background, analyst comment, paragraphs 4-9)

NEW YORK, Aug 5 (Reuters) - Growth in the U.S. services sectors decelerated in July to its weakest level in three years as trade worries weighed on business orders and the outlook for the overall economy, a private survey released on Monday showed.

The Institute for Supply Management (ISM) said its non-manufacturing activity index fell to 53.7 from 55.1 the month before. Analysts polled by Reuters had forecast a reading of 55.5 for July.

A reading above 50 indicates expansion in the sector.

Slower growth in the services sector, which accounts for more than two-thirds of U.S. economic activity, comes at a time that the U.S.-China trade war has been squeezing manufacturers.

"For an economy that is so heavily dependent on the service sector, this is a particularly troubling release," Ian Lyngen, head of U.S. interest rates strategy at BMO Capital Markets wrote in a research note.

The ISM services survey's measure on new orders fell to 54.1 last month, its lowest since August 2016, from 55.8.

A barometer on new export orders fell to 53.5 from 55.5 in June.

The latest reading on services prices fell to 56.5 from 58.9.

A lone bright spot was an uptick in the employment index, which moved up to 56.2 from 55.0. (Reporting by Richard Leong Editing by Nick Zieminski and David Gregorio)