150 people have died after a deadly crush on Saturday night in Seoul. 

The incident began when over 100,000 young people had descended on the popular night life province of Seoul, Itaewon. 

The area is famous in South Korea for its lively party atmosphere and many bars and restaurants.

Similar celebrations occured last year, but police were there to keep order and prevent people from going into busy areas.

This year around 5pm, witnesses claim, the streets began to get very busy with people posting on social media they felt unsafe.

People were crowded in a narrow alleyway from three directions, meaning they were unable to escape or move.

The worst part began at around 11pm, when people started to fall over on a slope, causing a massive crush in the crowd.

A witness said "people were suffocating, screaming... getting squeezed..."

Ambulances started arriving after 11pm.

Some eyewitnesses claim they saw friends trying to help by giving people who were unconcious CPR, but some of them died in their hands.

The ambulances struggled getting through the massive crowds of people and as a result even more people were suffocated. 

A few hours after the tragedy started unfolding, South Korea's President Yoon Suk-yeol announced his greatest sympathy for the victim's families  and said an investigation would be made into the cause of the crush.

"My heart is heavy and I struggle to cope with my grief." He said.

On Sunday morning he announced a period of national mourning.

The day after the incident, many shops, cafes and restaurants were closed, and the alleyways were sealed off.

Overall, 154 victims have been comfirmed as dead, mostly young people and teenagers, the majority women. Families are still searching for their children who went to the party and are missing.