01:27 PM EDT, 03/12/2026 (MT Newswires) -- US benchmark equity indexes tumbled intraday, while Brent briefly crossed $100 a barrel as worries grew that oil flow disruptions will continue amid an intensifying conflict in the Middle East.

The Nasdaq Composite was down 1.4% at 22,397.2 after midday Thursday, while the Dow Jones Industrial Average fell 1.2% to 46,868.1. The S&P 500 lost 1.1% to 6,695.7. Among sectors, industrials saw the biggest drop, while energy paced the gainers.

Brent jumped 8.1% to $99.43 a barrel intraday, after rising to as high as $101.53 earlier on Thursday. West Texas Intermediate crude oil gained 8.3% to $94.47.

Iran's new Supreme Leader Mojtaba Khamenei reportedly said the Strait of Hormuz -- the world's most important chokepoint for crude flows -- should remain shut. Mojtaba is the son of the former leader, Ayatollah Ali Khamenei, who was killed in the US and Israel strikes.

Mojtaba sought the immediate closure of US military bases in the Middle East, saying those bases will be attacked, according to media reports.

On Wednesday, two drones fell near Dubai's main airport, while Bahrain evacuated some planes, Reuters reported.

US Energy Secretary Chris Wright told CNBC Thursday that America was "not ready" to escort oil tankers through the strait.

"There are no signs of de-escalation in the Persian Gulf, so there is no end in sight to the disruptions to oil flows through the Strait of Hormuz," ING Bank said in a report.

The International Energy Agency slashed its oil output growth forecast for this year, saying the ongoing conflict in the Middle East is creating the largest supply disruption in the history of the global crude market.

On Wednesday, the agency agreed to release a record volume of 400 million barrels of oil reserves amid concerns around supply disruptions.

"There are concerns about the speed at which this oil will reach the market and whether it will be enough to tie up the market until we see oil flowing through the Strait of Hormuz again," ING said. "The only way to see oil prices trade lower on a sustained basis is by getting oil flowing through the Strait of Hormuz. Failing to do so means that the market highs are still ahead of us."

US Treasury yields were higher intraday, with the 10-year rate up 3.9 basis points at 4.25% and the two-year rate adding 9.2 basis points to 3.73%.

In economic news, weekly applications and continuing claims for unemployment insurance in the US fell sequentially, government data showed.

"It is unlikely that the fallout from the conflict in Iran and the resultant increase in energy prices will lead to an increase in layoffs, but this remains an area to watch," Jefferies said in a note. "More likely, the increase in uncertainty will lead to lower hiring rather than outright layoffs."

In company news, Dollar General ( DG ) posted better-than-expected fiscal fourth-quarter results, though the discount retailer's full-year same-store sales growth is forecast to slow on an annual basis. The company's shares were down 4.9% intraday.

Dow (DOW) was among the top gainers on the S&P 500, up 8.4%, as Citigroup upgraded the stock to buy from neutral and raised its price target to $40 from $28.

Adobe (ADBE), Ulta Beauty ( ULTA ) and Lennar ( LEN ) are expected to report their latest quarterly financial results after the closing bell Thursday.

Gold was down 0.8% at $5,138 per troy ounce, while silver fell 0.1% to $85.42 per ounce.