U.S. stock index futures indicated a mostly higher open Thursday after ECB President Mario Draghi extended but did not increase the amount of the central bank's asset purchase program.
Futures quickly gave up gains on the news before attempting to trade slightly higher.
"There doesn't seem to be a change in the amount of monthly purchases outside of the money that will be reinvested. As I and some suspected, the dollar is a sell on the news and the selling right now is sharp as the details of more QE are out are not the big bang that some had though and/or hoped for," Peter Boockvar, chief market analyst at The Lindsey Group said in a note.
Draghi said in a speech the European Central Bank would extended to at least March 2017 its massive 60 billion euro ($63.5 billion) a month bond-buying scheme.
Dow futures tried to hold mild gains after earlier falling about 90 points. Nasdaq and S&P futures attempted to hold higher after initially turning lower.
The U.S. dollar index fell more than 1 percent to near 98.5 after hitting a plus-12-year high of 100.51 Wednesday. Theeuro extended earlier gains to climb above $1.08.
Treasury yields held higher, with the recovering to trade higher near 0.96 percent and the 10-year yield at 2.22 percent.
The German 10-year yield briefly jumped to near 0.59 percent. European stocks gave up gains to trade sharply lower, with the German DAX down more than 2.5 percent.
Earlier, U.S. stock index futures pared gains slightly but continued to trade higher after the European Central Bank cut its deposit rate to negative 0.30 percent from negative 0.20 percent, while leaving the refinancing rate unchanged at 0.05 percent.
Fed Chair Janet Yellen is set to testify before Congress on Thursday and reiterate why the Fed believes it could raise interest rates for the first time in nine years as soon as this month. Her comments Wednesday sent the U.S. dollar index briefly to its highest since April 2003.
Other Fed speakers on Thursday include Fed Vice-Chairman Stanley Fischer, who will speak on financial stability and shadow banks at the Federal Reserve Bank of Cleveland Financial Stability Conference in Washington, D.C.
In economic news, initial jobless claims rose to 269,000. Both ISM nonmanufacturing data and factory orders are due at 10:00 a.m.
In oil markets, Brent crude traded at around $43.33 a barrel on Thursday, up about 2 percent, while U.S. crude was at around $40.52 a barrel, up nearly 1.5 percent as of 7:50 a.m., ET. The Organization of Petroleum Exporting Countries (OPEC) is set to meet in Vienna tomorrow.
In Europe, the pan-European Stoxx 600 index was around 0.71 percent higher on Thursday morning.
— CNBC's Patti Domm contributed to this report