Harsh spotlights and street lamps illuminate a vicious brawl between two furious shirtless men as the screams of a crowd echo beneath a Bangkok underpass: Fight Club Thailand is on.

In the capital city of a country renowned for its highly technical martial arts scene, amateur fighters gather regularly promising to exchange only blood and bruises in the underground club.

Fighters are allowed to go all-out against each other in a single three-minute round, but the bouts are not entirely no-holds-barred
Fighters are allowed to go all-out against each other in a single three-minute round, but the bouts are not entirely no-holds-barred AFP / Lillian SUWANRUMPHA

While the bout resembles a particularly frenzied boxing match, the setting -- surrounded by shipping containers in a poor port-side neighbourhood -- is a far cry from the glitzy charms of Muay Thai boxing stadiums.

"Here you don't have to know how to fight. You just need to have heart and that's it," club co-founder Chana Worasart told AFP.

The 30-year-old founded the club in 2016, partly inspired by the cult Brad Pitt movie, to allow amateur fighters to test their skills -- or just vent their aggression.

Bangkok's fight club was founded in 2016, and is meant to allow amateur fighters to test their skills and vent their aggression
Bangkok's fight club was founded in 2016, and is meant to allow amateur fighters to test their skills and vent their aggression AFP / Lillian SUWANRUMPHA

"I think the popularity is due to a variety of occupations and fighting styles that are different from the styles in the (professional) ring," he said.

That's certainly the appeal for 23-year-old contestant and grocery store owner Surathat Sakulchue.

The group has become a local sensation, with its private Facebook group racking up 73,000 members
The group has become a local sensation, with its private Facebook group racking up 73,000 members AFP / Lillian SUWANRUMPHA

"It's quite different (from traditional fights)," he told AFP, expecting to dish out -- and absorb -- punishment using all four limbs.

Plus, he added, "fighting with containers surrounding us is just fun and exciting."

Bangkok Fight Club co-founder Chana Worasart says the group is trying to balance regulating fights with maintaining its underground identity
Bangkok Fight Club co-founder Chana Worasart says the group is trying to balance regulating fights with maintaining its underground identity AFP / Lillian SUWANRUMPHA

Unlike the movie's famous line banning fighters from talking about their club to outsiders, the Bangkok-based outfit calls itself "the ring that will change violence into friendship".

Fights can get very violent, but participants are strictly barred from elbowing, grappling, throwing opponents to the ground or punching the backs of their heads
Fights can get very violent, but participants are strictly barred from elbowing, grappling, throwing opponents to the ground or punching the backs of their heads AFP / Lillian SUWANRUMPHA

The group has become a local sensation, with a private Facebook group racking up 73,000 members as word spread of the underground matches.

Fighters are allowed to go all-out in a single three-minute round -- with neither a winner or loser declared -- but the bouts aren't quite no-holds-barred.

Elbowing, grappling, throwing opponents to the ground and punching to the back of the head are strictly prohibited.

When the club first began, there were no clear rules, but now participants must agree to fighting guidelines, screening processes and a risk-acceptance pledge
When the club first began, there were no clear rules, but now participants must agree to fighting guidelines, screening processes and a risk-acceptance pledge AFP / Lillian SUWANRUMPHA

Unsurprisingly, the gatherings have not escaped the notice of the Thai police.

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Meanwhile, the club insists it is not governed by the Boxing Act, meaning organisers are not holding unsanctioned fights.

Co-founder Chana says the group is approved by the Department of Provincial Administration.

"I don't oppose the idea of turning this into legal, sanctioned fights, but at the same time, we can't lose the underground identity, so the question is 'where is the balance?'"

It is all a far cry from the scrappy club's beginnings, when there were no clear rules.

Now there are fighting guidelines, screening procedures, a risk-acceptance pledge as well as protective equipment and on-scene medical care.

"We don't ask fighters to kill each other. If you're too tired or too injured to go on, then we'll stop the fight," said Chana as another bout began.

After paying his respects with folded hands and touching gloves with his opponent, amateur fighter Ilya Ostroushchenko gets to work.

Landing a kick to his opponent's torso, Ostroushchenko bashes out a combination of punches, and a left hook to the face finally sends his opponent stumbling to the rubber mat.

The crowd enthusiastically roars "Somchai" -- a traditional, masculine Thai name given to the Russian -- as the bout finishes.

"My hands shake. My knees shake also, but when I go out to the centre, I feel good," he said.