At least 151 people were killed and 133 others were injured in South Korea's biggest catastrophe in years when a crowd of primarily young people celebrating Halloween in Seoul was trapped and crushed.

After the congestion in the capital's leisure district of Itaewon on Saturday night, emergency responders and pedestrians desperately attempted CPR on those laying in the streets.

According to Choi Seong-beam, chief of Seoul's Yongsan fire station, those killed or injured were largely teenagers and persons in their twenties. The fatalities included at least one foreigner, according to the Ministry of Interior, whose nationalities were not immediately announced. Because a couple of injured individuals were in serious condition, the death toll could increase even higher.

The State Department confirmed to CBS News on Sunday that at least two Americans were killed in the rush.

Officials first stated that 150 individuals had been hurt as of Sunday morning, but later revised their figure.

Officials with the National Fire Agency did not immediately explain the reason behind such a miscount but stated that as rescue operations progressed, emergency workers would have had a more accurate estimate of the casualties, and some of the injured would have been changed to deaths.

It was also likely that some of those who had suffered minor injuries had returned home and were no longer counted.

An estimated 100,000 people had congregated in Itaewon for the largest outdoor Halloween celebrations in the country since the outbreak began. In recent months, the South Korean government relaxed COVID-19 restrictions.

Itaewon is an expat-friendly neighborhood known for its trendy pubs, clubs, and restaurants, located near the former headquarters of US military troops in South Korea before they relocated out of the capital in 2018.

More than 1,700 response personnel from across the country were deployed to the streets to aid the injured, including 520 firefighters, 1,100 police officers, and 70 government workers. The National Fire Agency, on the other hand, indicated that officials were still attempting to identify the exact number of emergency patients.

It was unknown what drew the gathering into the narrow downhill lane near the Hamilton Hotel, a popular party spot in Seoul. According to one witness, after being pushed by one another, numerous people collapsed and toppled one another "like dominoes."

According to the Seoul-based Hankyoreh newspaper, the survivor, Kim, said they were stuck for approximately an hour and a half before being rescued, while some people yelled "Help me!" and others were out of breath.

According to the newspaper, another survivor, Lee Chang-kyu, saw about five to six guys start shoving others before one or two started falling one by one at the start of the stampede.

The stampede is the worst calamity since 304 people, largely high school students, died in an April 2014 ferry sinking. The sinking exposed lax safety norms and regulatory shortcomings since it was partly blamed on excessive and poorly tied cargo, as well as a crew that was ill-prepared for emergency scenarios.

The stampede on Friday will almost certainly lead to widespread criticism of government authorities for what they've done to strengthen public safety standards after the boat accident.

TV images and photos showed ambulances lined up in the streets, surrounded by cops, and emergency workers transporting the injured on stretchers. CPR was also performed on people laying in the streets by emergency personnel and passersby.

Paramedics were observed in one part monitoring the status of a dozen or more persons who lay still under blue blankets.

Hwang Min-hyeok, one of the visitors to Itaewon, told news channel YTN that seeing rows of victims stretched out in the alley near Hamilton Hotel was horrifying. He claimed that initially, emergency personnel was swamped, leaving people struggling to provide CPR to the injured laying on the streets. People wailed next to the dead, he claimed.

Another survivor in his twenties said he avoided being trampled when he luckily got into a pub whose door was open in the alley, according to Yonhap news agency.

According to a woman in her twenties, named Park, she and others were standing on the side of the alley while others were caught in the middle.

South Korean President Yoon Suk Yeol released a statement urging officials to guarantee that those injured receive prompt medical attention and that the safety of the celebration places is reviewed. He also directed the Health Ministry to deploy disaster medical support teams as soon as possible and to obtain beds in local hospitals to treat the injured.

The Seoul Metropolitan Government sent out emergency text messages asking residents to return home as soon as possible.

"Jill and I extend our heartfelt sympathies to the families who have lost loved ones in Seoul," President Biden stated in a statement Saturday evening.

"We join the people of the Republic of Korea in their grief and wish all those injured a fast recovery. Our two countries' alliance has never been more lively or vigorous, and the bonds between our people are stronger than ever. During this tragic occasion, the United States stands with the Republic of Korea."

There have been fatal stampedes in South Korea in the past. In 2005, a pop concert stampede in the southern city of Sangju killed 11 people and injured over 60 more. A teenage girl died and hundreds of others were injured after a stampede during a New Kids on the Block concert in Seoul in 1992.