US stocks fell and oil prices surged Monday morning as tensions over the Iran war heated up again, after President Trump announced the US Navy had seized an Iranian cargo vessel and Tehran sent mixed signals on resuming talks. The S&P 500 and Nasdaq had slumped 0.2% and 0.4%, respectively, as of 9:45 a.m. Eastern Time, while the Dow Jones Industrial Average traded roughly flat. Brent crude oil prices jumped 3.9% to $93.89 and West Texas Intermediate rose 4.5% to $86.29. National average