Stock index futures held higher, with the Dow Jones industrial average futures up about 10 points.
The presentation of new budget proposals by the anti-austerity Greek government has raised hopes that Athens will be able to secure a cash-for-reforms deal with its international creditors. A deal is seen a key to averting a default that could end with Greece's exit from the euro zone with potentially destabilizing ramifications for global markets.
Read More Clock ticks for Greece after 'major' step forward
"Given the scale and breadth of the budgetary concessions Greece makes in its latest offer, we doubt Prime Minister (Alexis) Tsipras would be willing or able to top this up with additional consolidation measures, posing the risk of renewed stand-off in case of an unfavourable assessment by the Institutions," analysts at Daiwa Capital Markets said in a note.
The European Central Bank on Tuesday lifted the ceiling on emergency liquidity to Greek banks for a second time in two days, Reuters cited a banking source as saying.
The U.S. Treasury auctions $26 billion in 2-year notes at 1 p.m. Treasury yields extended gains, with the 10-year yield near 2.41 percent, while the dollar rose nearly 1 percent against major world currencies. The euro fell to trade below $1.12, while the yen approached 124 yen against the dollar.
In corporate news:
BlackBerry–The handset maker missed estimates on both the top and bottom lines, but its tech and software licensing revenue jumped from a year earlier and its adjusted profit margins were also above expectations.
Darden Restaurants–The Olive Garden parent reported adjusted quarterly profit of $1.08 per share, 15 cents above estimates, with revenue also beating. Darden also said it would pursue a spin-off of its real estate assets into a REIT, followed by a leaseback of the properties involved.
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AT&T–The stock was upgraded to "overweight" from "neutral" at Barclays, which cited the potential positive effects of AT&T's purchase of DirecTV.
—CNBC's Peter Schacknow contributed to this report.