The plush toys, resembling a rabbit-like monster, have surged in popularity after endorsements from celebrities such as Rihanna and Dua Lipa.

Their limited availability has drawn buyers from abroad to the UK, with Pop Mart -- the distributor of Labubu dolls -- seeing overnight queues and chaotic scenes outside its flagship stores.

"This product, it has many, many fans from everywhere in the world and in some countries, it's not available for purchase, so there's many, many people who come to London just to purchase them," Engie, a supervisor at Pop Mart in London, told AFP.

"People wait for hours queuing up in front of the store and it's so sad to see them be disappointed, because the resellers create a really difficult environment for them, or they get violent... and we have nothing left for them," she added.

She said the store had adopted a ticketing system to manage the crowds but that tensions had escalated.

"Some people even try to buy those (tickets) from other people... and if they don't sell it to them, they end up threatening them," she said.

"They actually end up threatening us as staff... and that makes them get physical as well, trying to touch us."

Pop Mart confirmed the suspension of physical sales on Instagram, citing safety risks.

"While this speaks to the love and excitement surrounding Labubu and The Monsters, it's important for us to ensure a safe, fair, and comfortable shopping experience for everyone -- both our customers and our store teams," the company said.

The frenzy has led to a wave of thefts and assaults internationally.

In Singapore, CCTV footage captured a family stealing Labubu dolls from a claw machine, according to Singaporean online media outlet AsiaOne.

In California, The Sun reported a car break-in in which three Labubu toys were taken.

"It's just not safe to take it outside at the moment," said UK collector Rayy Raphael, 30, who noted prices had reached 500 pounds (675 dollars) for rare dolls.

"There's so many TikTok trends at the moment of, like, how people are getting punched," he said.

Another fan, 24-year-old Mia Mills, lamented how difficult it had become to find the toys.

"It's very rare they do have them," she said.

"I've been collecting them for a long while now."

Pop Mart said online sales would continue and that it was working on a new distribution model to ensure fairness.