"Fell Like Dominoes": How South Korea's Halloween Tragedy Unfolded

The crowd appears in good spirits and calm at first, but then a commotion begins and people start being pushed and pressed into one another.

More than 150 people were killed and scores more were injured in a deadly stampede at a packed Halloween event in central Seoul late Saturday, officials said, in one of South Korea's worst-ever accidents.

South Korea's President Yoon Suk-yeol declared a period of national mourning Sunday, saying the government would pay for the medical care of those injured and the funerals of those who died.

The crowd surge and crush happened in the capital's popular Itaewon district, where local reports said as many as 100,000 people -- mostly in their teens and 20s -- had gone to celebrate Halloween, clogging the area's narrow alleyways and winding streets.

"In the centre of Seoul, a tragedy and disaster occurred that should not have happened," Yoon said in a national address.