Seoul, South Korea (CNN) -- The South Korean military apologized Monday for shooting at a commercial airplane carrying 119 passengers and crew.

The Asiana Airlines flight was preparing to land Friday morning at Incheon International Airport, 70 kilometers (43 miles) west of Seoul, when two soldiers fired at the aircraft after mistaking it for a North Korean military jet.

The soldiers were on Gyodong Island near the North Korean border. After firing 99 rounds, they reported the incident.

The South Korean military claims the rounds were only warning shots from K-2 rifles, and there was no damage to the aircraft because it was out of range.

"I sincerely apologize for causing the public concern over the incident," Col. Lee Bung-Woo, spokesman for the Joint Chiefs of Staff, said Monday.

The aircraft, on its way from Chengdu, China, was "flying on its regular route under command of the flight control tower," Asiana Airlines spokesman Ki Won Suh said.

Asiana confirmed two other flights flew on the same route 20 minutes before and after the firing incident, raising questions about why only one flight concerned the soldiers. The passengers and pilots were unaware they had been fired upon until they landed.

"We understand the guards need more education on how to distinguish civilian airplanes," said Lee, the military spokesman. But the South Korean military said it will not reprimand the two soldiers because they acted in accordance with procedure.

The incident comes at a time of heightened tensions between the two Koreas. Pyongyang said it would cut off all ties with Seoul last month, accusing the South of waging psychological warfare by sending propaganda into North Korea undermining the regime.

CNN's Jiyeon Lee contributed to this report