U.S. stock index futures edged lower on Wednesday as investors worried about the possibility of a recession from aggressive policy tightening awaited minutes from the Federal Reserve's meeting last month.

Stock markets have been roiled in recent weeks as central banks across the world look to aggressively raise borrowing costs to stem a surge in inflation.

With Fed policymakers pushing for large interest rate hikes, traders are now bracing for another 75-basis-point rate hike later in July.

Investors will look for clues on the pace of future rate hikes when the minutes from Fed's June 14-15 policy meeting are released at 2 p.m. ET (1800 GMT).

The U.S. central bank raised its policy rate by three-quarters of a percentage point, its biggest hike since 1994 at the end of that meeting.

The Ukraine conflict, decades-high inflation and the Fed's pivot away from easy-money policy pushed the S&P 500 to its steepest first-half percentage drop since 1970. The index is down nearly 20% so far this year.

A key part of the U.S. Treasury yield curve stayed inverted for a second straight day on Wednesday, reflecting growing angst in the world's biggest bond market over recession risks.

With the second-quarter earnings season around the corner and economic data pointing to a slowdown in consumer spending, investors will be watching out for company forecasts and commentaries to gauge the growth trajectory of the U.S. economy.

A survey from the Institute for Supply Management slated for release at 10:00 a.m. ET (1400 GMT) is likely to show U.S. services industry activity slowed for the third month in a row.

A slew of data on U.S. employment is also due this week, including the June nonfarm payrolls report on Friday that will be parsed for clues on economic health.

At 6:59 a.m. ET, Dow e-minis were down 35 points, or 0.11%, S&P 500 e-minis were down 5.5 points, or 0.14%, and Nasdaq 100 e-minis were down 22.25 points, or 0.19%.

Shares of Amazon.com Inc fell 0.2% in premarket trading after Britain's antitrust watchdog started an investigation into the online retail giant.

Altria Group Inc rose 2.7% after the U.S. health regulator temporarily stayed the marketing denial order on Juul Labs Inc's e-cigarettes.

Uber Technologies Inc and DoorDash Inc fell 2.8% and 6.5%, respectively, after Amazon.com agreed to take a 2% stake in Just Eat Takeaway.com's struggling U.S. food delivery business Grubhub.