At least 146 people were killed and 150 others were injured in a stampede during Halloween festivities in Seoul, officials said of one of the biggest disasters in South Korea that will likely raise serious questions about public safety standards.

The massive death toll is being tallied after people were crushed by a large crowd pushing forward in a narrow alley in Seoul's Itaewon neighborhoods, a major leisure and night-life district in the capital.

Choi Seong-beom, chief of Seoul's Yongsan fire department, said the death toll could rise and that an unspecified number among the injured were in critical conditions following the stampede in Itaewon on Saturday night.

He said that the bodies were being sent to hospitals or a gym, where bereaved family members could identify them. He earlier said most of the dead and injured are in their 20s.