South Korean fighter jets mistakenly dropped eight bombs on a civilian district on Thursday, injuring 15 people and damaging houses and a church during military exercises in Pocheon, the Air Force and fire agency said.

The fire agency said in a statement that 15 people were wounded, including two who were seriously hurt.

Pocheon is about 40 kilometres  northeast of Seoul, near the heavily militarized border with North Korea.

“There was a sudden loud roar of a fighter jet, then an explosion rang out.. When I went to the scene, there were about four houses that were halved from the damage, people hurt,” said Oh Moung-su, a 65-year-old resident.

“Dusk and smoke rose into the sky, water gushed out of a pipe. People in a vehicle going to a construction site were injured -— some of them couldn’t even get out of the car. Another was outside the car covering his eye.”

South Korea’s Air Force said eight 225-kilogram Mk82 bombs from two KF-16 jets fell outside the shooting range during joint live-fire exercises.

“We are sorry for the damage caused by the abnormal drop accident, and we wish the injured a speedy recovery,” the Air Force said in a statement.

The accident was due to a pilot entering incorrect coordinates, said a military official who declined to be identified because of the sensitivity of the matter. The official said that the two jets then dropped four bombs each, with all of them detonating.

Authorities would suspend live-fire exercises until there was a clear understanding of what went wrong, but the incident would not affect major joint South Korean and U.S. military exercises due to begin on Monday, the official said.

Residents in the area have protested about the disturbance and potential danger from nearby training grounds for years.

Photographs from the scene showed a house hollowed out by the impact, shattered windows and a church building strewn with debris.

Security camera footage aired on local TV also caught the moments leading up to the incident, with a pickup truck driving on a tree-lined street before the area is consumed by a large explosion.

“The unthinkable has happened,” said Pocheon city mayor Baeck Young-hyeun, who urged the government and military to come up with measures to prevent any further civilian damage.

The defense ministry said earlier on Thursday that South Korea and U.S. forces were holding their first joint live-fire exercises in Pocheon, linked to annual military drills due to start next week.

The Freedom Shield joint drills, which will run from March 10 to 20, aim to strengthen the readiness of the alliance for threats such as North Korea, the Seoul’s Joint Chiefs of Staff (JCS) said before the accident.

This year’s drills will reflect “lessons learned from recent armed conflicts” and North Korea’s growing partnership with Russia, it added.

“Our planners look across the globe and identify the trends that are changing and we look at how we can incorporate that into our exercises,” Ryan Donald, a spokesperson for the United States Forces Korea (USFK), told a media briefing on Thursday.

About 70 combined field training sessions are scheduled for this year’s exercise, said Lee Sung-jun, a spokesperson for Seoul’s JCS.