In late trading in New York, the Dow Jones Industrial Average fell 0.69 per cent, the Standard & Poor's 500 Index declined 0.52 per cent while the Nasdaq Composite Index dropped 1.19 per cent.
The outlook helped underpin the already-strong appeal of the safest fixed-income securities. The US Treasury sold US$21 billion of 10-year notes at a record low rate.
"There is a grab for high-quality paper internationally," Carl Lantz, head of interest-rate strategy in New York at Credit Suisse, one of 21 primary dealers that bid at the auction, told Bloomberg News. "With things in Europe not getting better, and the data in the US softening, demand for Treasuries is high and going to stay that way."
US Commerce Department data released today showed the trade deficit shrank 3.8 per cent to US$48.7 billion in May. Exports rose 0.2 per cent, while imports declined 0.7 per cent.
Exports might not hold up though.
"While the positive momentum in export activity provides some encouragement on the tone of overall global economic activity, it is unlikely to be sustained," Millan Mulraine, an economic strategist at TD Securities in New York, told Reuters.
In Europe, the Stoxx 600 Index eked out a gain of less than 0.1 per cent for the session.
As expected the Spanish government detailed a fresh round of austerity cuts, bowing to pressure from its EU partners to do more to balance its books and avert the need for a full-scale bailout.
On a positive note, the European Banking Authority says the region's bank have successfully recapitalised themselves - mostly on their own - even though challenges remain.