At least 151 people have been killed in a crowd crush as Halloween celebrations were under way on a narrow street in the South Korean capital, Seoul, authorities have said.

At least 82 others were injured, 19 of them seriously, in the crush in the city’s Itaewon district on Saturday night.

Here is what you need to know:

What happened?

• The disaster took place after about 10pm local time (13:00 GMT) on Saturday after a huge crowd celebrating Halloween thronged a narrow alley in the entertainment district of Itaewon.
• The first calls for help came at around 10:15pm (13:15 GMT), according to the Yonhap news agency.
• More than 800 emergency workers, including 346 firefighters, and 140 rescue vehicles were deployed to treat the injured, fire officials said.
• Police confirmed dozens of people were given cardiopulmonary resuscitation (CPR) on the streets, while others were taken to nearby hospitals.

Many killed, injured

• At least 151 people were killed, and 82 others were injured during the incident. Authorities said the death toll could increase further as emergency crews continued rescue efforts.
• “People were layered on top of others like a tomb. Some were gradually losing their consciousness while some looked dead by that point,” the Yonhap news agency cited a witness as saying.
• Choi Seong-beom, a fire official, said most of the victims were women and young people in their 20s.
• Those killed included 19 foreigners, Choi said. They include people from Iran, Uzbekistan, China and Norway, he said.
• A doctor who administered first aid to victims described scenes of tragedy and chaos. “When I first attempted CPR there were two victims lying on the pavement. But the number exploded soon after, outnumbering first responders at the scene,” Lee Beom-suk told local broadcaster YTN. “So many victims’ faces were pale. I could not catch their pulse or breath and many of them had a bloody nose. When I tried CPR, I also pumped blood out of their mouths.”
• Several videos posted on social media appeared to show people performing CPR on victims lying in the street. Other videos appeared to show dozens of people covered with blue plastic sheets at the roadside.
• Seoul’s Metropolitan government said it has received reports about 355 missing people following the crowd crush.