Stock futures tumbled Sunday night as tensions between the U.S. and Iran escalated over the weekend with the seizure of an Iranian-flagged cargo ship.

Dow Jones Industrial Average futures

shed 425 points, or 0.9%. S&P 500 futures

lost 8%, along with Nasdaq-100 futures

President Donald Trump on Sunday said the U.S. had fired on and seized an Iranian-flagged cargo ship in the Gulf of Oman. This comes after Iran declined to join another round of peace talks in Pakistan planned by the U.S.