Fireworks go off at the 19th Busan Fireworks Festival at Gwangalli Beach in Suyeong-gu, Busan, Saturday. (Yonhap)

An unexpected lighting failure that occurred during the 19th Busan Fireworks Festival on Saturday was caused by three teenagers, according to the event’s organizers on Sunday.

The teens' unauthorized entrance into the control room for the festival led to the light failure, according to the organizing committee of the annual festival in the second-largest Korean city. The teens touched a cable connected to light controls on the bridge Gwangandaegyo while being escorted out by security, causing a communications error that was unable to be fixed during the show.

Lights on the 7.4-kilometer bridge were supposed to illuminate in harmony with the fireworks. Officials were unable to repair the lights despite delaying the show for 10 minutes for maintenance.

"(The teens) abruptly broke into the control room. ... We will prepare backup facilities to respond to unexpected situations for the next year's event," the committee officials were quoted as saying.

Held each year at the Gwangalli Beach in Suyeong-gu, Busan Fireworks Festival is one of the most popular and largest fireworks festivals in the country, along with the Seoul International Fireworks Festival. An estimated 1.03 million people participated in this year's event, up from around 770,000 at last year's festival.

Due to it being a premier event in the city, the Busan Metropolitan Government dispatched 6,700 city and police officials for safety, extending the operation of the city's subways to aid those gathered at the beach area.

Fireworks light up the night's sky at the 19th Busan Fireworks Festival at Gwangalli Beach in Suyeong-gu, Busan, Saturday. (Yonhap)