(Updates with index/price moves and geopolitical news from the first paragraph.)
US equity indexes slid as Iran-backed Houthi attacks on Saudi Arabian energy sites pushed crude oil and government bond yields in the United States higher.
The Dow Jones Industrial Average dropped 1.1% to 52,853.3, the Nasdaq Composite declined 0.3% to 26,434.4, and the S&P 500 retreated 0.5% to 7,684.5 ahead of Tuesday's close. Energy, utilities and real estate were the trio of gainers. Healthcare and financials led decliners.
Iran's Fars news agency reported an explosion in the southern Jask area of the Islamic Republic, after reports of earlier explosions heard on the country's Kharg Island, Al Jazeera, a Middle Eastern broadcaster, reported.
This comes as Yemen's Tehran-backed Houthis attacked energy facilities and cities in US ally Saudi Arabia on Tuesday, wounding more than 70 people and underscoring the risk of the Iran conflict escalating into a wider regional war, Reuters reported. Saudi Arabia said the attacks stopped operations at several energy facilities in the kingdom's south, Bloomberg reported, while noting a pick-up in buying by China, the world's largest importer.
The front-month US West Texas Intermediate crude oil contract jumped 2.3% to $93.62 per barrel, and global benchmark North Sea Brent advanced 1.6% to $98.54 per barrel.
US Treasury yields rose, with the two-year up 1.7 basis points to 4.40% and the 10-year higher by 1.4 basis points to 4.80%.
In company news, Novartis (NVS) sank nearly 14% after the company said its phase 3 Harbor study evaluating delpacibart etedesiran in patients with myotonic dystrophy type 1 failed to meet its primary endpoint of video hand opening time. Amgen's (AMGN) experimental heart drug olpasiran may still show a meaningful reduction in major cardiovascular events, even after Novartis' competing drug failed in a large study, UBS Securities said Monday in a report. Shares slumped more than 10%, the worst performer on the S&P 500, the Nasdaq, and the Dow.