At least 19 people have been killed in wildfires sweeping across southeastern South Korea, as authorities confirmed Wednesday that a firefighting helicopter crashed during efforts to contain the blazes.

Three victims were found in Andong, the capital of North Gyeongsang Province, three in Cheongsong, six in Yeongyang, and seven more in Yeongdeok, according to Seoul-based Yonhap News. Another person remains missing in Cheongsong, while 10 others have been reported injured, including two in serious condition.

A 73-year-old pilot was killed when his S-76 helicopter—reportedly in service for 30 years—crashed while battling the fires in Uiseong, located about 180 kilometers southeast of Seoul. Following the incident, all firefighting helicopters were grounded by authorities.

Acting President Han Duck-soo described the wildfires as “the worst ever” in the country’s history and called for “all-out efforts” to stop their spread.

The acting president said the fires have so far burned 17,000 hectares, destroyed 209 homes and factories.

The blaze also forced the evacuation of about 500 inmates from a prison in North Gyeongsang Province.

The flames also gutted the historic Gounsa Temple in Uiseong, originally built in 681 AD by a Buddhist monk during the Silla Dynasty. Cultural officials moved the temple’s 9th-century Stone Seated Buddha and other historical artifacts to safety before the fire reached the site.

Thousands of firefighters, dozens of helicopters, and emergency vehicles have been deployed since the fires began last Friday in Sancheong County, South Gyeongsang Province. Fueled by strong, dry winds, the wildfires have since spread rapidly north to Uiseong, Andong, Cheongsong, Yeongyang, and Yeongdeok.