Washington, Oct 2 (IANS): Economic activity of the US manufacturing sector continued to see slower expansion in September, indicating a strong dollar might continue constraining the factory activities, an industry survey showed.

The manufacturing index, also known as the purchasing managers index (PMI), registered 50.2 last month, the third straight decline and the weakest since May 2013, Xinhua news agency cited the Institute for Supply Management (ISM) report on Thursday.

The index registered at 51.1 in August. 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 50.1 in September, the lowest point since August 2012, the production index decreased 1.8 points from August to register at 51.8 in September, and the employment index fell 0.7 point from the previous month to 50.5 in September.

Businesses surveyed reported their concern about the global economy and customer confidence, said the survey.

Only seven of the 18 manufacturing industries tracked by the ISM reported growth in September, while 11 industries reported contraction in the month.