US stock markets opened lower on Thursday, while crude oil prices rose above $100 a barrel as doubts over the durability of the US-Iran ceasefire weighed on investor sentiment, the AP reported.The S&P 500 slipped 0.1%, while the Dow Jones Industrial Average fell 40 points, or 0.1%, and the Nasdaq Composite dropped 0.2% in early trading after a strong rally in the previous session.Markets turned cautious after the United States, Iran and Israel disagreed over the terms of a two-week ceasefire, raising concerns of fresh disruptions to energy supplies.Oil prices jumped sharply, with US crude rising 6.8% to $100.79 a barrel, after reports that Iranian forces had mined the Strait of Hormuz, a key global oil transit route.Global benchmark Brent crude rose 3.7% to $98.24 a barrel, well above pre-war levels of around $70, though below the peak of $119 seen during the rising tensions.Analysts said oil prices could remain high due to uncertainty over the ceasefire. Macquarie strategists said upward pressure on prices may remain as the risk of renewed conflict and supply disruptions remains.On Wall Street, stock-specific moves were mixed. Simply Good Foods fell 15.1% after reporting a steeper-than-expected decline in revenue, with CEO Joe Scalzo calling the performance unsatisfactory.In contrast, Constellation Brands gained 5.3% after posting better-than-expected quarterly results, although it withdrew forward guidance citing “limited near-term visibility.”Mixed economic data also weighed on sentiment. A core inflation estimate for February came in slightly higher than expected, while jobless claims rose more than expected, pointing to possible softening in the labor market.Bond markets remained volatile, with the yield on 10-year US Treasuries rising to 4.31% from 4.29%, reflecting concerns over persistent inflation and increased borrowing costs.Analysts said sustained high oil prices could complicate the Federal Reserve’s rate trajectory, with policymakers considering the possibility of raising rates if inflation pressures persist.Global markets also weakened, with South Korea’s Kospi falling 1.6% and Germany’s DAX falling 1.4%.