Wall Street was set to open lower on Friday as caution mounted ahead of a high-stakes US-China trade meeting at the G20 Summit, whose outcome would determine if the trade war that has roiled financial markets would abate or worsen.

Futures, however, gave up some losses after Trade Representative Robert Lighthizer said he would be surprised if Saturday's dinner between US President Donald Trump and China's Xi Jinping "wasn't a success".

Markets have faced conflicting headlines in the run up to the two-day meeting of 20 industrialized nations in Buenos Aires, where all eyes would be on the trade talks between the world's two largest economies that have imposed tariffs on hundreds of billions of dollars of each other's imports.

President Donald Trump said on Thursday he was close to making a deal but was not sure if he wants to do it, while news that Trump's hardline trade adviser Peter Navarro, will attend the meeting between Trump and Xi, added to worries.

"People don't want to get too optimistic heading into a meeting, because the president is kind of a wild card," said Robert Pavlik, chief investment strategist and senior portfolio manager at SlateStone Wealth LLC in New York.

"You don't know how tough he'll be with this meeting and these negotiations."

So far this week, dovish comments from Federal Reserve Chair Jerome Powell and the latest Fed minutes have helped the benchmark S&P 500 rise 4 percent, setting it on course to post its biggest percentage gain in nine months.

At 8:46 a.m. ET, Dow e-minis were down 86 points, or 0.34 percent. S&P 500 e-minis were down 7.25 points, or 0.26 percent and Nasdaq 100 e-minis were down 10.75 points, or 0.16 percent.

General Electric shares fell 2.4 percent in premarket trading after the Wall Street Journal reported several former employees told the US securities regulator the company failed to acknowledge worsening results in the insurance business.

Marriott International Inc dropped 4.1 percent after the company said a guest reservation database of its Starwood Hotel brand was breached, potentially exposing information on about 500 million guests.

HP Inc rose 1.5 percent after its quarterly revenue beat analysts' estimates on Thursday, driven by growth in its personal systems business.