SEOUL - Flammable materials on the outside of a building fueled a major blaze that killed 29 people, experts said on Friday, evoking comparisons with the Grenfell Tower disaster in London.

The fire engulfed an eight-story tower in the southern city of Jecheon, killing 29 people and injuring 29 more. Twenty of the dead were found at a women's sauna and others elsewhere in the building, which also houses a fitness center and restaurants.

President of the Republic of Korea Moon Jae-in on Friday made a surprise visit to the site. He was briefed on damage situations, ordering officials to focus on follow-up measures to minimize casualties.

Experts said the structure was a fire trap waiting to happen, with insufficient emergency exits, flammable finishing materials and illegally parked cars blocking access to fire trucks.

Street surveillance video footage showed orange flames and black smoke billowing from the ceiling of a ground floor parking lot underneath the building, which stood on pillars.

The fire spread quickly upward along the outside walls of the tower, which was made of cheap and highly flammable finishing materials.

"There were three or four exploding sounds and I saw the fire on the ground floor quickly jump upward along the outside walls," said one eyewitness.

It reportedly took only seven minutes for the entire building to be engulfed in smoke and flames.

Professor Chung Sang-man at Kongju University said the tower had cladding material made of a cement and foam sandwich, which are widely used for insulation but prone to spreading fire.

"Flammable finishing materials have been a great source of problem in major blazes," he said, citing the Grenfell Tower inferno in June that killed 71 people.

The London fire started with a faulty refrigerator on the fourth floor of the building owned by the local authority, but rapidly spread up the 24-story tower, which had new cladding on the outside.

In the wake of the disaster, hundreds of similar buildings across Britain were subjected to safety checks, and some residents were evacuated as a precaution.

The painstaking process to identify all the remains took months, and anger is still simmering among the survivors, with most awaiting permanent housing and voicing skepticism about an official inquiry.

On Friday, experts said buildings such as the Jecheon fitness center are especially vulnerable to fires that begin on the ground floor as staircases act like smokestacks, making flames spread upward quickly.

Vehicles in the garage under the building also ignited, fueling the blaze.

Toxic fumes and flames were sucked rapidly upstairs to reach the first floor sauna, suffocating victims who had no escape but a narrow smoke-filled exit.

Afp - Xinhua