Prime Minister Prayut Chan-o-cha said on Sunday he was deeply saddened to learn of the crowd surge that killed more than 150 people, including one Thai national, during Halloween celebrations in Seoul's Itaewon district.
Government spokesman Anucha Burapachaisri said the prime minister was shocked to hear about the loss of life and injuries, adding he has ordered state agencies to closely monitor the situation and provide assistance to Thais affected by the tragedy.
One Thai woman was among the 22 foreigners from 12 countries who died in the crowd crush on Saturday night. More than 80 people were injured.
"The prime minister has expressed his condolences to those who lost their lives and those who were injured in the incident," the spokesman said.
AFP reported more than 150 people were killed in the crush at a Halloween event in central Seoul, with South Korea's president vowing a full investigation into one of the country's worst disasters.
The crowd surge and crush took place in the capital's popular Itaewon district, where police estimated as many as 100,000 people -- mostly in their teens and 20s -- went to celebrate Halloween on Saturday night, clogging the area's narrow alleyways and winding streets.
President Yoon Suk-yeol declared a period of national mourning, telling the country in a televised address that "a tragedy and disaster occurred that should not have happened".
He said the government "will investigate the cause of the incident and make fundamental improvements to ensure the same accident does not occur again in the future".
"My heart is heavy and it is difficult to contain my sorrow," he added, before he visited the scene of the disaster and spoke to emergency workers.
Eyewitnesses described being trapped in a narrow, sloping alleyway, and scrambling to get out of the suffocating crowd as people piled on top of one another.
The fire department said at least 153 people, including 22 foreigners, were killed, and 82 people were injured in the stampede, which occurred around 10pm Seoul time.
Most of the victims were young women in their 20s, it said.
A street in Itaewon district is full of people before a crowd surge during Halloween festivities killed and injured many in Seoul, South Korea. photos by Yonhap via REUTERS
The Interior Ministry said most victims had now been identified.
"The high number of casualties was the result of many being trampled during the Halloween event," fire official Choi Seong-beom told reporters at the scene, adding that the death toll could climb.
Seoul authorities said they had also received 355 reports of missing people by early yesterday. Officials said yesterday they had no clear idea of what caused the crush, while eyewitnesses described scenes of chaos as a vast crowd panicked in a narrow alleyway.
Some Thai tourists who witnessed the tragedy posted video clips and described the chaos. A Facebook user who goes by the name "Jessi Jassicah" said she was seated in a venue when the tragedy took place and the four million won (106,000 baht) she had paid for a table there saved her life.
According to her, about 50 people were found dead in front of the venue and it was tragic that she could not help anyone to safety as all the guests were locked inside and security guards did not let anyone in or out during the mayhem.
Jane, another Thai tourist at the scene, said the area was crowded, but not out of the ordinary for this time of the year. However, she said at one point the crowd became so densely packed that she was dragged off her feet.
"There was no smoke, no gas leak. I felt the pressure of people around me and everybody just screamed," she said.
Actress Wannarot Sonthichai received overwhelming messages of concerns after she tweeted "I'm in Itaewon right now.. omg" on Saturday night. She later told her followers that she was safe.