U.S. stock index futures indicated a sharply lower open on Wednesday as worries over China's relentless selloff and Greece's debt crisis weighed on investor sentiment.
Dow Futures trimmed losses, trading about 140 points lower amid news that Greece was closer to submitting concrete proposals. Earlier, futures were as much as 200 points lower, following another painful trading session in China which saw stocks close down nearly 6 percent, following an 8 percent slide earlier in the session.
The Shanghai Composite has fallen more than 30 percent from its mid-June peak amid frequent bouts of extreme volatility and analysts say the turbulence is starting to unnerve regional investors.
Commodities were hit on Tuesday on mounting China fears and remained under pressure in Wednesday trade.
The Federal Open Market Committee (FOMC) minutes will also be in focus, with traders scanning the Federal Reserve's June meeting report for hints on interest rate rise timing.
Greek- and Chinese-related developments should continue to dominate market focus, but the minutes of that FOMC meeting Wednesday should get the market's attention when released at 2 p.m. ET
Meanwhile, the Greek government has until Friday morning to present detailed reform proposals to allow a bailout deal by a Sunday summit.
Greek Prime Minister Alexis Tsipras addressed the European Parliament on Wednesday, lambasting Europe's advocacy of austerity and the efficacy of Greece's bailout programs since 2010, but promised a detailed, "concrete" deal would be presented in the next two to three days.
Other data due for release on Wednesday include consumer credit data at 3 p.m. ET. Major earnings include aluminium producer Alcoa, which is expect to report after market close.