Rescuers attend to victims on a street in Seoul's Itaewon district, Oct. 30, after more than dozens of people were reported to be in cardiac arrest from a stampede during Halloween parties the previous day. (Yonhap)

At least 151 people have been killed and 82 others injured in a deadly stampede in Seoul's Itaewon district as huge crowds of partygoers, many in their late teens and 20s, converged in the entertainment district for late-night Halloween celebrations.

The deadliest stampede in Korea's history happened Saturday night in a narrow downhill alley near Hamilton Hotel in the famous nightlife district after tens of thousands of people visited the area for Halloween.

People pack a street in Itaewon in central Seoul, Oct. 29, as many come out to enjoy Halloween festivities before a deadly stampede during the celebration. Yonhap

As of 9 a.m. Sunday, a total of 151 people, including 19 foreigners, have been killed and 82 others injured, 19 of them seriously, according to Choi Seong-beom, head of the fire department in Yongsan, which includes Itaewon.

Of the deceased, 97 are female and 54 are male, Choi said.

The foreigners killed include those from Iran, Uzbekistan, China and Norway, he said.

The stampede marked the worst tragedy in Korea since the 2014 sinking of the ferry Sewol that killed 304 people, mostly high school students.

It was the first Halloween event in Seoul in three years after the country lifted many COVID-19 restrictions. Most of the people on the streets were wearing Halloween costumes.

Victims in their late teens and 20s accounted for the age group most affected by the accident, the authorities also said. It is not yet known whether the victims included minors.

Police investigators scrutinize an alley in Seoul's Itaewon district, Oct. 30, following a deadly stampede the previous day during Halloween celebrations. Yonhap

Video footage showed rescue workers and ordinary people conducting CPR on victims on the streets.

Fire authorities initially received dozens of reports from people in the Itaewon area about patients with breathing difficulties. The first report was made around 10:15 p.m.

Witnesses and survivors say a massive group of people surged into the downhill alley with a width of about 4 meters and were instantly pushed down by others.

"People kept pushing down into a downhill club alley, resulting in other people screaming and falling down like dominos," an unidentified witness wrote on Twitter. "I thought I would be crushed to death too as people kept pushing without realizing there were people falling down at the start of the stampede."