Young people flocking to Seoul's popular Itaewon district on Saturday for the first virtually unrestricted Halloween festivities in three years instead found themselves caught up in a deadly crush that killed at least 151 people.

The crowd of partygoers, some still in their teens and many clad in Halloween costumes, was ready to enjoy the bars, nightclubs and restaurants where the revelry routinely spills over into narrow and often steep side streets.

But the intimacy of Itaewon's backstreets turned sinister this Halloween weekend.