At least 120 people were killed Saturday and some 100 were injured in a stampede in central Seoul when thousands crowded into narrow streets to celebrate Halloween, officials said.

Fire Department official Choi Seong-beom said the stampede took place around 10 pm (1300 GMT) and many of the victims were trampled to death.

"The high number of casualties was the result of many being trampled during the Halloween event," Choi said, adding that the death toll could climb.

The Yonhap news agency quoted an unidentified witness as saying he saw victims crushed to death.

"People were layered on top of others like a tomb. Some were gradually losing their consciousness while some looked dead by that point," the witness said, according to Yonhap.

Choi added that 74 bodies were sent to local hospitals and 46 were put in a nearby gym.

Officials had said earlier that 50 people were in cardiac arrest and that more than 140 ambulances were dispatched to the scene to aid the victims.

The stampede took place near the Hamilton Hotel in the vibrant district of Itaewon and a large number of people were believed to have entered a narrow alley near the hotel, the Yonhap news agency reported.

President Yoon Suk-yeol ordered officials to dispatch first aid teams and to swiftly secure hospital beds for those affected, the presidential office said.

Meanwhile, Seoul Mayor Oh Se-hoon, who was on a visit to Europe, decided to return home in the wake of the accident, Yonhap reported, citing city officials.