A firefighting helicopter crashed into a residential area of South Korea's southern city of Gwangju on Thursday, killing all five firefighters on board, officials said.

The chopper crashed into an uncrowded street near a huge apartment complex in the city's housing area of Gwangsan-gu around 10:50 a.m., they said.

A female high school student on the ground sustained a minor injury after getting hit by a fragment of the helicopter, the officials added.

The helicopter was returning to its headquarters in Gangneung, about 237 kilometers east of Seoul, after participating in search operations for 11 people still missing from the April 16 ferry disaster, they said.

 

The firefighting agency said the firefighters arrived aboard the helicopter at the ferry sinking site off the country's southwest coast on Monday.

According to witnesses, the helicopter caught fire in the air before nosediving into the street.

"A plume of black smoke rose with a loud bang," said a witness. "I thought it was thunder and lightning."

The officials said they were investigating the exact cause of the incident and assessing the damage.

Meanwhile, the National Emergency Management Agency said the helicopter was not one of the old models that needed to be replaced.

"The AS365N3 helicopter was introduced in 2001," said an official. "The service life of firefighting helicopters is usually 20 years." (Yonhap)