•Raphael Rashid, a freelance journalist, told the BBC there were "tens of thousands of people - the most I've ever seen. So many people - to the point we were being crushed on the pavement".
Witnesses have described scenes of utter chaos when the narrow streets of Seoul's popular Itaewon nightlife district became choked with people, in crowds which suffocated them.
Raphael Rashid, a freelance journalist, told the BBC there were "tens of thousands of people - the most I've ever seen. So many people - to the point we were being crushed on the pavement".
Thousands of teenagers and adults in their 20s had descended on Itaewon in Halloween costumes, thrilled that they could finally party after two years of Covid restrictions in South Korea.
But video clips of the disaster showed real-life horror unfolding, with one witness likening the disaster to a war movie. More than 150 died, more than 80 were injured.
The clips showed crowds jammed so tight that they could barely move; a few managing to climb out to safety; desperate bystanders helping paramedics to give CPR to victims; a long line of victims in bodybags on the pavement.
A steeply sloping alleyway became a death trap - apparently the crowd surged forward and people at the front fell over and were trampled by those behinds.
Some video clips on Twitter show rescuers desperately tugging at people to extract them from a crowd jammed tight.
"A short person like me could not even breathe," said a female eyewitness quoted by AFP news agency. She said she had survived as she was at the edge of the alleyway, while "people in the middle suffered the most".
Raphael Rashid said "no one really understood what was going on" and some police were "standing on top of their police cars desperately trying to tell people to leave the area as soon as possible".
A medic at the scene, Dr Lee Beom-suk, told local broadcaster YTN he had tried to revive a few victims with CPR, but "the number exploded soon after, outnumbering first responders at the scene". "Many bystanders came to help us with CPR."
He said "so many victims' faces were pale". "I could not catch their pulse or breath and many of them had a bloody nose."
Park Jung-hoon, 21, told Reuters the situation had been "completely out of control".
And Moon Ju-young, also 21, said "there were way too many people and it was too crowded".
"I know the policemen and rescue workers are working hard, but I would say there was a lack of preparation."
An Itaewon resident, 53-year-old Lee Su-mi, told Reuters that "those young people who were called 'Covid generation' could finally celebrate Halloween as their first festival.
"Then no one was able to foresee the festival turned into a disaster."