U.S. stock-index futures signaled a lower open on the last day of the week, as fears about the Ukraine-Russia situation resurfaced.
Ukrainian troops killed several pro-Russian rebels on Thursday, and Russian troops started military exercises close to its border with Ukraine.
Standard & Poor's cut its currency rating on Russia, as capital continues to flow out of the country amid heightened tensions with the West. S&P downgraded Russia's foreign currency rating to one notch above "junk" status at BBB-/A-3, down from BBB/A-2.
"In our view, the tense geopolitical situation between Russia and Ukraine could see additional significant outflows of both foreign and domestic capital from the Russian economy and hence further undermine already weakening growth prospects," the ratings agency warned.
In the U.S., companies reporting first quarter earnings before Wall Street opens include Ford, Colgate-Palmolive, Moody's and State Street. These follow after-hours results from Amazon and Microsoft, both of which beat sales expectations. Microsoft also topped analysts' forecasts for earnings per share.
Ford posted lower-than-expected profit as the No. 2 U.S. automaker increased warranty reserves in North America for older vehicles by $400 million. (Click here for the latest quote.)
The dollar declined against the currencies of major U.S. trading partners, and the 10-year Treasury yield used in figuring mortgage rates and other consumer loans fell 2 basis points to 2.66 percent.
In early New York trade, gold futures for June delivery rose $9.60, or 0.7 percent, to $1,300.20 an ounce; crude-oil futures fell 60 cents, or 0.6 percent, to $101.34 a barrel.
Friday's session will see the final version of April's University of Michigan consumer confidence reading, along with the Markit services purchasing managers' index (PMI).