US stock futures fell on Monday as tensions between the US and Iran intensified over the weekend amid renewed disruptions in the Strait of Hormuz. Dow futures dropped nearly 1%, while S&P 500 and Nasdaq 100 futures declined 0.8% and 0.6%, respectively. President Donald Trump said the US Navy fired on and seized an Iranian-flagged cargo vessel in the Gulf of Oman after it ignored warnings to stop while departing Hormuz. Tehran also targeted ships and reversed plans to reopen the Strait following the US refusal to lift its blockade on Iranian ports. While optimism had been building late last week, uncertainty has since returned, even as Trump signaled that US negotiators would travel to Pakistan on Monday for further talks. Last week, the S&P 500 and Nasdaq Composite rallied 4.54% and 6.84%, respectively, with both benchmarks reaching fresh record highs, while the Dow advanced 3.19% for its third consecutive weekly gain.