Washington, Sep 1 (IANS): Economic activity of the US manufacturing sector in August expanded at the slowest pace since May 2013, indicating a strong dollar might continue constraining the factory activities, an industry survey showed on Tuesday.

The manufacturing index, also known as the purchasing managers index (PMI), registered 51.1 in August, down from July's reading of 52.7, the Institute for Supply Management (ISM) said in a report on Tuesday. The index has fallen for two consecutive months.

A reading above 50 percent indicates the sector is generally expanding, while a reading below the ratio indicates contraction.

The ISM's new-orders index fell to 51.7 in August, compared to July's reading of 56.5; the production index decreased 2.4 points from July to register at 53.6 in August; and the employment index also fell 1.5 points from July's reading of 52.7 to 51.2 in August.

Businesses surveyed reported the positive impact of lower raw materials prices, but expressed continuing concern over export growth, said the survey.

Ten of the 18 manufacturing industries tracked by the ISM reported growth in August, while six industries reported contraction in the month.