South Korea begins probe into deadly Halloween crush

South Korean investigators combed footage on Monday from more than 50 state and private closed-circuit TV cameras as well as from social media looking for answers to how a surge in Halloween party-goers trapped in narrow alleys killed so many.

As the country began a week of mourning, the death toll climbed to 154. Another 149 people were injured, 33 of them in serious condition. At least 26 citizens from 14 countries were among the dead, Reuters reports.

South Korean President Yoon Suk-yeol called for a thorough investigation, and authorities said they were focused on reconstructing the lead-up to the surge and looking at whether anyone may have been responsible for triggering the crush.

"We are analysing CCTVs to find out the exact cause of the accident," Police chief investigator Nam Gu-jun told reporters.

"We will continue questioning more witnesses, including nearby shop employees," he said.

Tens of thousands of revellers - many in their teens and twenties and dressed in costume - had crowded into narrow streets and alleyways of the popular Itaewon district on Saturday for the first virtually unrestricted Halloween festivities in three years.

Chaos erupted when people poured into one particularly narrow and sloping alley, even after it was already packed, witnesses said.

Prime Minister Han Duck-soo, who steers a task force team handling the accident, said the identification of the victims was nearly complete and funeral preparations could move ahead, promising support for the bereaved families.