(CNBC) — U.S. stocks were hammered on Monday, with benchmark indexes falling through key support levels after a gauge of factory activity disappointed, heightening concern about the economy before Friday’s monthly jobs report.

Stocks had wavered ahead of the report that had U.S. manufacturing expanding at a substantially slower pace in January, driving overall factory activity to an eight-month low.

“A report like this scares people ahead of the payroll number on Friday,” said Andres Garcia-Amaya, global market strategist at J.P. Morgan Funds, who added the report’s soft new orders component was of particular concern.

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