U.S. stock index futures edged lower on Friday with investors awaiting November payrolls data at the end of a volatile week marked by fears about the Omicron coronavirus variant slowing an economic recovery.

Equity markets flitted between gains and losses all week as investors digested updates on the newly detected variant, which is spreading globally and causing many countries to reimpose travel restrictions.

The main three indexes are on course for weekly losses, with Wall Street's fear gauge, the CBOE Market Volatility index , spiking above 30 for the first in ten months earlier this week.

The Labor Department's closely watched nonfarm payrolls report, due at 8:30 am ET, is expected to show U.S. employers stepped up hiring in November, with the unemployment rate seen falling to a 20-month low of 4.5% and wages increasing further.

"Assuming the Omicron news remains less end of the world, a print above 550,000 jobs should see the faster Fed-taper trade reassert itself," said Jeffrey Halley, senior market analyst at Oanda.

"That may nip the equity rally in the bud, while the U.S. dollar and U.S. yields could resume rising."

Federal Reserve Chair Jerome Powell said earlier this week that the U.S. central bank will consider at the upcoming meeting a faster wind-down to its bond-buying program, a move widely seen as opening the door to earlier interest rates hikes.

November reading on ISM non-manufacturing PMI report is also scheduled after markets open.

At 6:42 a.m. ET, Dow e-minis were down 48 points, or 0.14%, S&P 500 e-minis were down 7.75 points, or 0.17%, and Nasdaq 100 e-minis were down 25.5 points, or 0.16%.

Meanwhile, the Democratic-controlled U.S. Senate passed a bill to fund the government through mid-February, averting the risk of a shutdown.

Delta Air Lines and Norwegian Cruise Line led losses among shares of major airlines and cruiseliners, down 1.0% and 0.7%, respectively, in premarket trading after logging sharp gains on Thursday.

Ulta Beauty jumped 6.3% in low volumes after the beauty retailer raised annual sales and profit forecasts.

Nucor Corp rose 1.6% after the steel products manufacturer increased its quarterly dividend by 23% and announced a $4 billion buyback program.