Seoul, South Korea — Two South Korean fighter jets accidentally dropped eight bombs on a civilian area during training Thursday, injuring at least eight people, officials said. One report put the number at 15.

The 500 pound MK-82 bombs released by the KF-16 fighter jets fell outside a firing range and caused civilian damage, the air force said in a statement.

The air force said it will establish a committee to investigate why the accident happened and examine the scale of the civilian damage. It said the fighter jets were taking part in the air force’s joint live-fire drills with the army.

The incident occurred at about 10 a.m. local time, Agence France-Presse reported.

An unidentified air force official told local reporters a pilot of one of the KF-16s put in a wrong coordinate for a bombing site. An unidentified Defense Ministry official also told reporters more investigation was needed to find out why the second KF-16 also dropped bombs on a civilian area.

The contents of the officials’ briefing were shared with foreign media.

The air force apologized and expressed hopes for a speedy recovery of the injured people. It said it will actively offer compensation and take other necessary steps.

The accident happened in Pocheon, a city close to the heavily armed border with North Korea.

In a televised briefing, Pocheon Mayor Paek Young-hyun called the bombings “awful” and urged the military to halt drills in the city until it formulates reliable steps that can prevent a recurrence. He said Pocheon, a city of 140,000 people, provides three major firing ranges for the South Korean and U.S. militaries.

The military said it’s decided to suspend live-fire drills in Pocheon, but the Reuters news agency cited an official as saying major joint South Korean-U.S. military exercises set to start Monday wouldn’t be impacted.

Paek described Thursday’s training as a joint drill with the U.S. military. But the South Korean Defense Ministry couldn’t immediately confirm that.

Pocheon’s disaster response center said six civilians and two soldiers were injured and were being treated at hospitals. Four of the injured – all civilians – were in serious condition, the center said. Two of the seriously injured are foreigners – one from Thailand and the other from Myanmar.

The local fire agency said in a statement that 15 people were hurt, two seriously, Reuters reported.

Three houses were partially damaged along with a Catholic church and a greenhouse but they didn’t appear to have been directly hit by the 2 bombs, according to the Pocheon center.

Residents in the area have expressed alarm about the potential danger from the nearby training grounds for years, Reuters notes.