Raw steel production in the country's Great Lakes region dropped to 640,000 tons and overall U.S. output also declined in the week that ended Saturday, according to an American Iron and Steel Institute estimate.
Great Lakes production plunged by about 21,000, or about 3.3 percent, from the week prior. Most of the raw steel production in the Great Lakes region takes place in Indiana and the Chicago area.
Production in the Southern District, typically the country's second biggest steel-producing region, rose to 647,000 tons, up from 630,000 tons a week earlier.
Total domestic raw steel production last week was about 1.83 million tons, down from 1.85 million tons a week earlier.
U.S. steel mills had a capacity utilization rate of 76.3 percent last week, down from 77 percent a week earlier. The capacity utilization rate had been 78.3 percent at the same time last year.
Domestic mills have produced an estimated 13.8 million tons of steel this year, a 1.1 percent decrease from the 13.99 million tons produced during the same period last year.
U.S. steel mills shipped 7.6 million net tons in December, a 0.4 percent increase over November and a 2 percent increase from December 2012. Hot-rolled sheet shipments rose 9 percent, and cold-rolled shipments went up by 1 percent.
Hot-dipped galvanized sheet and strip products did not fare as well, declining by 4 percent.