Oil prices leaped and stocks slumped Friday on worries that escalating violence following Israel’s attack on Iranian nuclear and military targets could damage the flow of crude around the world, along with the global economy.

The S&P 500 sank 1.1% and wiped out what had been a modest gain for the week. The Dow Jones industrial average dropped 769 points, or 1.8%, and the Nasdaq composite lost 1.3%.

The strongest action was in the oil market, where the price of a barrel of benchmark U.S. crude jumped 7.3% to $72.98. Brent crude, the international standard, rose 7% to $74.23 for a barrel.

Iran is one of the world’s major producers of oil, though sanctions by Western countries have limited its sales. If a wider war erupts, it could slow the flow of Iran’s oil to its customers and keep the price of crude and gasoline higher for everyone worldwide.

Companies that use a lot of fuel as part of their business fell to some of the sharpest losses. Cruise operator Carnival dropped 4.9%. United Airlines sank 4.4%, and Norwegian Cruise Line Holdings fell 5%.

They helped overshadow gains for U.S. oil producers and other companies that could benefit from increased fighting between Israel and Iran.

Exxon Mobil rose 2.2%, and ConocoPhillips gained 2.4% because the leaping price of crude portends bigger profits for them.

Contractors that make weapons and defense equipment also rallied. Lockheed Martin, Northrop Grumman and RTX all rose more than 3%.

The price of gold climbed as investors searched for safer places to park their cash. An ounce of gold added 1.4%.

Often, prices for Treasury bonds will likewise rise when investors are feeling nervous.

That sent the yield on the 10-year Treasury up to 4.41% from 4.36% late Thursday.

Elsewhere on Wall Street, Adobe fell 5.3% even though the company behind Photoshop reported a stronger profit for the latest quarter than Wall Street expected.

All told, the S&P 500 fell 68.29 points to 5,976.97. The Dow dropped 769.83 to 42,197.79, and the Nasdaq composite sank 255.66 to 19,406.83.

— Associated Press