Equities on Wall Street and in Europe fell overnight as disappointing import data from China renewed concern about the global economy and corporate profits at the start of a fresh quarterly US earnings season.
JPMorgan and Intel are set to report their earnings after the market close.
Last month the US Federal Reserve held off on raising its target interest rate, and while policy makers have since reminded investors a 2015 hike remains on the table, not all officials agree.
"Right now my expectation is, given where I think the economy would go, I wouldn't expect it would be appropriate to raise rates," Fed Governor Daniel Tarullo told CNBC when asked if interest rates should rise this year.
Meanwhile Louis Fed President James Bullard acknowledged it would be challenging for US policy makers to hike rates at this month's meeting, October 27-28.
"It is very tough for the committee to make a big decision and then change it after only one meeting," Bullard said, Reuters reported. "Roughly speaking the data has not been that different from what would have been expected, and the jobs report was weaker."