South Korean President Yoon Suk Yeol issued a statement calling for officials to ensure swift treatment for those injured and review the safety of the festivity sites.
He also ordered disaster medical teams to be deployed.
It was the first Halloween event in Seoul in three years since the country lifted Covid restrictions and social distancing.
Seoul's mayor Oh Se-hoon, who was visiting Europe, decided to return home in the wake of the accident.
Yoon declared a period of national mourning and expressed his condolences to the victims, mostly teenagers and people in their 20s, and his wishes for a speedy recovery to the many injured.
He said: "This is truly tragic.
"A tragedy and disaster that should not have happened took place in the heart of Seoul."
Prime Minister Rishi Sunak reacted in horror to the crush, saying: "Horrific news from Seoul tonight.
Witness Raphael Rashid arrived in the area around 7pm local time and not long after panic erupted as "more and more" people flooded in.
He told the BBC: "So many people - to the point we were being crushed on the pavement, to the point where we had to spill onto the road where there were cars.
"No one really understood what was going on."
AFP news agency said 140 ambulances were scrambled to the scene as the horror erupted just before 10.20pm (1.20pm GMT)Â before taking victims off on wheeled stretchers.
Authorities in Seoul said dozens of people collapsed and went into cardiac arrest after being crushed.
"All our thoughts are with those currently responding and all South Koreans at this very distressing time."
On Sunday, Sen. Amy Klobuchar (D., Minn.), urged Congress to consider extending protection to congressional leaders’ houses as well as expanding the number of members who get protection. Mrs. Klobuchar suggested security from local police, or the U.S. Marshals Service.
“There can be various levels of protection,” she said on NBC’s “Meet the Press.” “It doesn’t have to be the kind of full-out protection you see for people who are in the line of succession to the presidency. But certainly, there has to be a different level of threat that allows members to get protection.”
The Capitol building itself is highly fortified, with metal detectors at each entrance and a significant U.S. Capitol Police presence. That security didn’t prevent the attack on the Capitol on Jan. 6, 2021 or the shooting of Rep. Steve Scalise (R., La.) at a baseball practice in Virginia in 2017.
Congress has been on edge over the personal security of members for years, but recent threats have prompted lawmakers to explore more expansive protective measures. In July, the House sergeant at arms announced a program to provide up to $10,000 to cover the cost of installing and maintaining security systems at members’ personal residences.
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Some congressional offices have spent the weekend reviewing security protocols at their respective lawmakers homes and reviewing security protocols, said one Democratic aide.Â
“In my little corner of the world, we’re very freaked out,” said the aide, who said lawmakers saw the attack as an attempted assassination against the speaker.'
During the Drink Champs podcast, West alleged that Floyd died from a fentanyl overdose. In the same interview, which has since been taken down by YouTube, West also made anti-Semitic comments.Â
In May 2020, Floyd’s death sparked international outrage and sparked a global conversation about police brutality in the US after white Minneapolis police officer Derek Chauvin pressed his knee against the neck of the unarmed black man for a total of nine minutes and 29 seconds during an arrest outside a Cup Foods grocery store.
In April 2021, Chauvin was found guilty of three murder and manslaughter charges and is now serving two prison sentences concurrently of more than 22 years. Three other officers involved in the incident received lighter sentences.
