Oil prices leaped, and stocks slumped 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% Friday and wiped out what had been a modest gain for the week. The Dow Jones Industrial Average dropped 769 points, and the Nasdaq composite lost 1.3%.
Crude prices jumped roughly 7% because Iran is one of the world's major producers of oil and fighting in the region could disrupt the flow.
Treasury yields rose with worries about inflation.
On Friday:
The S&P 500 fell 68.29 points, or 1.1%, to 5,976.97.
The Dow Jones Industrial Average fell 769.83 points, or 1.8%, to 42,197.79.
The Nasdaq composite fell 255.66 points, or 1.3%, to 19,406.83.