South Koreans flocked Monday to memorials honoring the 154 people killed in a crowd surge at Halloween celebrations, as authorities faced accusations that lax crowd control had caused the disaster.

Mourners wept, prayed, and placed flowers at a huge official altar set up in central Seoul for victims — mostly young women — of the Saturday crush, with many railing against authorities' failures to prevent the catastrophic loss of young life.

"I am devastated by what happened, they were just trying to have a good time," 19-year-old student Hwang Gyu-hyeon told AFP, weeping and struggling to speak clearly, as she explained how the deaths of so many people her own age had affected her.

"I pray for the victims. I can't believe this accident happened despite the signs that were clear beforehand. Nothing was done to prepare for this crowd," she said.

Song Jung-hee, 69, said she kept thinking about how "excited and spirited" the young victims must have been, eager to enjoy a night out without Covid restrictions for the first time in three years.

"If only there had been more police officers to keep order, this would not have happened," she told AFP.

At a makeshift memorial outside a subway station in the popular Itaewon nightlife district, where the tragedy occurred, dozens of mourners gathered, many wiping away tears as they placed white chrysanthemum and bottles of soju on the altar.

One sign left at the memorial said: "At an age when you all were all about to blossom like flowers… My heart is broken. I pray all the souls will rest in peace in heaven."

Police failures

Calls for accountability were growing Monday in the press and online, as potential lapses of crowd control and policing emerged.

As many as 100,000 people — mostly in their teens and 20s, many wearing Halloween costumes — had poured into Itaewon's small, winding streets, with eyewitnesses describing scant security and no crowd control.

Police said at a briefing Monday they had deployed 137 officers to the event, pointing out that the number was significantly higher than previous years.

But local reports said many of the police deployed were focused on drug use, rather than crowd control.

"This was a disaster that could have been controlled or prevented," Lee Young-ju, a professor from the Department of Fire and Disaster at the University of Seoul, told broadcaster YTN.

"But this was not taken care of, with no one taking the responsibility in the first place."

Online, claims also spread that police this year were not actively managing the crowd, which allowed too many people to congregate around the subway station and in the alleyway at the epicenter of the disaster.

"I've lived in Itaewon for 10 years and experienced Halloween every year but yesterday was by no means particularly crowded compared to previous years," Twitter user @isakchoi312 wrote.

"Ultimately, I think the cause of the disaster was crowd control."

On Sunday, the government had defended the policing plan.

"(The crush) was not a problem that could be solved by deploying police or firefighters in advance," Interior Minister Lee Sang-min told a briefing.

South Korea is typically strong on crowd control, with the country's regular protest rallies often so heavily policed that officers can outnumber participants.

Protest organizers must by law report plans to authorities in advance, but there were no such requirements for the young people flocking to the Itaewon Halloween event.

Chaos, fear

Tens of thousands of partygoers were packed into the downhill alleyway, no more than three meters (10 feet) wide, with eyewitnesses describing scenes of chaos, as people pushed and shoved to get through, with no police in sight to guide or control the crowd.

Witnesses described being trapped in a narrow, sloping alleyway, and scrambling to get out of the suffocating crowd as people piled on top of one another.

Most of the 154 dead, including 26 foreigners, had been identified Sunday, with the education ministry confirming Monday that at least six young teenagers were among the victims.

But the toll could rise further with at least 33 people in critical condition, officials said.

The country started a week of national mourning, with entertainment events and concerts cancelled and flags nationwide flying at half-mast.