US stock futures slipped on Monday as Iran vowed retaliation to the US airstrikes on its nuclear facilities over the weekend.

Investors fear a broader conflict in the Middle East as Tehran warned that the US attack had expanded the scope of its military action.

At 07:43 AM ET, Dow E-minis were down 98 points, or 0.23%, S&P 500 E-minis were down 10.25 points, or 0.17%, and Nasdaq 100 E-minis were down 45.75 points, or 0.21%.

Oil prices climbed in a volatile session amid concerns around Iran shutting the Strait of Hormuz, a key oil supply route. Brent futures were up 1.2% at $77.91 a barrel as of 07:22 AM ET.