WASHINGTON (AP) — U.S. factory output slumped 0.5% in September, as a strike at General Motors caused a steep decline in auto production amid broader struggles for manufacturers.

The Federal Reserve said Tuesday that manufacturing production has fallen 0.9% over the past 12 months, a reflection of the disruptions and uncertainties caused by the U.S.-China trade war. The figures showed some stability, however, as factory output increased during the recently ended third quarter after having declined for the first six months of the year.

The G.M. strike, which began on Sept. 16, led to a 4.2% decline last month in the making of autos. The automaker reached a tentative 4-year deal this week with workers who took to the picket lines for a month, so automaking could rebound in November. Excluding autos, factory output slipped a more modest 0.1% in September.

Total industrial production, which includes mining and utilities as well as manufacturing, slipped 0.4% in September.

Mining output fell 1.3% last month because of less crude oil being extracted and fewer wells being drilled. Production at utilities improved 1.4% as warm weather boosted demand for electricity.

There was a slight decline in capacity utilization in September, a sign that the industrial sector is far from running at full speed. The capacity utilization rate was 77.5% in September, down from 77.9% in August.