U.S. factories grew last month at the fastest pace since June, helped by a jump in new orders and production.

The Institute for Supply Management, a trade group of purchasing managers, says its manufacturing index rose to 52.7 in November, up from 50.8 in October. Any reading above 50 indicates expansion.

Manufacturing has grown for 28 straight months, according to the index. Factories were among the first businesses to start growing after the recession officially ended in June 2009.

Factories added workers, but at a slower pace than the previous month.

U.S. manufacturers are facing strains overseas in key export markets. Europe is struggling with its financial crisis and China's growth has slowed.