Industrial production fell 0.4% in December, more than expected.
This was due to cutbacks in mining and utilities, according to the release from the Federal Reserve.
The 0.6% drop in the prior period was revised even lower to -0.9%.
The capacity-utilization rate during the month was 76.5%.
Economists had estimated that industrial production fell 0.2% month-on-month, while capacity utilization dropped to 76.8% from a revised 76.9%.
The data offer a window into the state of manufacturing, mining, and electric and gas utilities.