WASHINGTON (AP) — US factory activity expanded last month at the fastest pace in 2 ½ years, an encouraging sign that manufacturing could lift economic growth and hiring in the coming months.

The Institute for Supply Management, a trade group of purchasing managers, said Tuesday that its manufacturing index rose in September to 56.2, the highest since April 2011. That’s up from 55.7 in August and the fourth straight increase in the index. A reading above 50 indicates growth.