Factory activity in the U.S. mid-Atlantic region weakened in August as new orders fell and the pace of hiring slowed, a survey showed on Thursday.

The Philadelphia Federal Reserve Bank said its business activity index fell to 9.3 from 19.8 in July, undershooting economists' expectations for a reading of 15.0.

Any reading above zero indicates expansion in the region's manufacturing. The survey covers factories in eastern Pennsylvania, southern New Jersey and Delaware.

The new orders index fell to 5.3 from 10.2, while employment slipped to 3.5 from 7.7.

The survey is one of the first monthly indicators of the health of U.S. manufacturing leading up to the national report by the Institute for Supply Management. (Reporting by Steven C. Johnson; Editing by James Dalgleish)