Wind-driven wildfires that were among South Korea’s worst ever have ravaged the country’s southern regions, killing 24 people, destroying more than 200 structures and forcing 27,000 residents to evacuate, officials said Wednesday.

The death toll included a pilot who died after a helicopter crashed during efforts to contain a blaze in the south-eastern town of Uiseong, one of the hardest-hit areas. The aircraft had no other crew members. Police said that most of the dead are those in their 60s and 70s.

The National Fire Agency said at least 26 people sustained varying degrees of injuries.

An ancient Buddhist temple, houses, factories and vehicles were destroyed in the wildfires that have burned 17,535 hectares, the government’s emergency response centre said.

In a televised address, South Korea’s Acting President Han Duck-soo said the wildfires that began last Friday were worse than many previous ones.

“Damages are snowballing,” Han said.

“There are concerns that we’ll have wildfire damages that we’ve never experienced, so we have to concentrate all our capabilities to put out the wildfires in the rest of this week.”

Han said crews struggled to extinguish the wildfires because strong winds swept the areas overnight. He also said about 4650 firefighters, soldiers and other personnel were working on Wednesday with the help of about 130 helicopters, adding that “a small amount” of 5-10 millimetres of rain was expected on Thursday.

As of Wednesday evening, firefighters were tackling at least four active wildfires, including in the south-eastern coastal town of Yeongdeok, which alerted residents of the nearest village to evacuate to an indoor gymnasium.

Strong winds and smoke-filled skies forced authorities in the south-eastern city of Andong to order evacuations in two villages, including Puncheon, home to the Hahoe folk village — a UNESCO World Heritage Site founded around the 14th-15th century. Hikers were advised to leave the scenic Jiri Mountain, one of the country’s largest national parks, as another fire spread closer.

Observers say the ongoing wildfires are the third biggest in South Korea’s history in terms of land burned. The largest fires were in Andong, the neighbouring counties of Uiseong and Sancheong, and the city of Ulsan.

On Tuesday, officials said firefighters had extinguished most of the flames from the largest wildfires in those areas, but wind and dry conditions allowed them to spread again.

The blaze in Uiseong destroyed about 20 of the 30 buildings and structures at Gounsa, a temple said to be originally built in the 7th century. Among the burned structures were two state-designated “treasures” — a pavilion-shaped building erected overlooking a stream in 1668, and a Joseon dynasty structure built in 1904 to mark the longevity of a king.

Meanwhile, the Justice Ministry said it protectively removed 500 inmates from a detention centre in Cheongsong, another southern town, but no damages were reported to the facility.

The Korea Forest Service said it had raised its wildfire warning to the highest level nationwide, requiring local governments to assign more workers to emergency response, tighten entry restrictions for forests and parks, and recommend that military units withhold live-fire exercises.

Among the dead were four firefighters and government workers who died in Sancheong on Saturday after being trapped by fast-moving flames driven by strong winds, according to officials.

Government officials suspect human error caused several of the fires, possibly due to the use of fire while clearing overgrown grass in family tombs or sparks from welding work.