US manufacturing activity fell in October to its lowest level for 26 years, according to a new report from the Institute for Supply Management.
The report cited "significant demand destruction", for the third consecutive month in which the sector contracted.
The figures were far worse than the market had expected and pushed the Dow Jones index briefly into negative territory in early morning trading.
However, US construction spending in September fell far less than expected. The institute's index of national factory activity fell to 38.9 from 43.5 in September. Any score of less than 50 represents a contraction in manufacturing.
October's score is the lowest-recorded since September 1982. Every sector surveyed, apart from clothing and electronic products, reported a contraction for the month.
New orders, production, employment and supplier deliveries all fell, with only inventories of unsold goods increasing on September's score. Export orders fell for the first time following 70 consecutive months of growth.
Robert Macintosh, chief economist at Eaton Vance, described the figures as "pretty grim".
"It means we're in a recession, it's as simple as that - a pretty solid manufacturing recession," he said.
