SEOUL, South Korea — At least 15 people were injured in South Korea on Thursday after fighter jets accidentally dropped eight bombs on a civilian area during training linked to joint military drills with the United States, the South Korean Air Force and fire officials said.

The South Korean military said the training in Pocheon, a northeastern city of about 140,000 people near the heavily fortified border with North Korea, was in preparation for Freedom Shield, an annual U.S.-South Korea…