U.S. stock index futures fell on Tuesday, with technology shares leading the selloff, as worries over the impact of aggressive rate hikes, escalating Russia-Ukraine war and China ramping up COVID-19 measures darkened the economic outlook.

Markets have struggled to maintain the momentum of a brief rally early last week as a clutch of recent data continues to point to more policy tightening by the U.S. Federal Reserve that could tip the economy into a recession.

Most rate-sensitive growth stocks such as Microsoft Corp., Twitter Inc., Amazon.com, Apple Inc., and Tesla Inc. were down between 0.7% and 1.3% in premarket trading.

The yield on the benchmark 10-year U.S. Treasury note was up on Tuesday, hitting a day's high of 4.006%.

With recent economic indicators signaling persistent inflation going forward, money markets are pricing in a 92% chance of another 75-basis-point hike at the Fed's meeting in November.

A consumer prices report due on Thursday will provide some clarity on inflation, while minutes from the Fed's September meeting is also expected later in the week.

Belarus said on Tuesday that its forces had grouped with Russian troops on its borders as a defensive measure, further aggravating a spiraling war.

Shanghai and other big Chinese cities have ramped up COVID-19 testing amid a rise in infections, with some local authorities hastily closing schools, entertainment venues and tourist spots.

The CBOE volatility index, also known as Wall Street's fear gauge, rose to 33.57 points, up for a fourth straight session and inching closer to near two-weeks high.

At 6:09 a.m. ET, Dow e-minis were down 269 points, or 0.92%, S&P 500 e-minis were down 36.75 points, or 1.01%, and Nasdaq 100 e-minis were down 111.75 points, or 1.02%.