A part of a shanty in Seoul, South Korea’s capital, caught fire on Friday, burning 60 homes—many of which were made of cardboard and wood—and requiring the evacuation of about 500 residents.

The fire, which broke out before dawn in Guryong Village, a slum located directly across a highway from Seoul’s upscale Gangnam neighborhood, took emergency workers five hours to put out. Nobody has been hurt, according to officials, up to this far.

Home to around 1,000 people, Guryong is one of the last remaining shanty towns in the capital and has become a symbol of inequality in Asia’s fourth largest economy.

Ten helicopters and hundreds of firefighters, police and troops joined the effort to put out the blaze which, according to officials, razed almost one in ten of the 600-plus homes in Guryong.

“I saw a flash from the kitchen and opened the door, and flames were shooting from the houses next door,” said Shin, a 72-year-old woman whose home was completely burned in the inferno.

“So I knocked every door nearby and shouted ‘fire!’ and then called 119,” she said, giving only her surname.

Kim Doo-chun, 60, said his family was unaffected by the fire but he told Reuters that the village was constantly at risk of disaster due partly to its cardboard homes and narrow alleys.

“If a fire breaks out in this neighbourhood, the entire village could be in danger if we don’t respond quickly. So we’ve been responding together for decades,” said Kim, who has lived in the area for 30 years.

The slum has long been prone to fires and flooding, and safety and health issues abound.

The government had unveiled plans for redevelopment and relocation after a huge fire in late 2014, but those efforts have made little progress amid a decades-long tug of war between landowners, residents and authorities.

The civic authorities for Seoul and Gangnam district, and state-run developers have been at odds over how to compensate private landowners in Guryong and have yet to agree whether residents, most of whom are squatters, are entitled to government support for relocation and housing.

Informed about the fire while in Switzerland for the World Economic Forum, President Yoon Suk-yeol ordered all-out efforts to prevent a bigger disaster, his spokeswoman Kim Eun-hye said.

Seoul Mayor Oh Se-hoon visited the still smouldering village and asked officials to prepare to relocate affected families.