Issouf Sanogo / AFP - Getty Images

A pile of abandoned shoes in the street of Abidjian, Ivory Coast, on Wednesday. Sixty-one people died in a stampede at a New Year's Eve celebration there that also left dozens injured.

ABIDJAN, Ivory Coast -- Survivors of a stampede in Ivory Coast that killed 61 people, most of them children and teenagers, after a New Year's Eve fireworks display, said Wednesday that makeshift barricades stopped them from moving along a main boulevard, causing the crush of people.

Ivory Coast President Alassane Ouattara ordered three days of national mourning and launched an investigation into the causes of the tragedy but two survivors, in interviews with The Associated Press, indicated why so many died in what would normally be an open area, the Boulevard de la Republic.

An estimated 50,000 people had gathered in Felix Houphouet Boigny Stadium and elsewhere in Abidjan's Plateau district to watch the fireworks. As they streamed away from the show some encountered blockades.

"Near the Justice Palace we were stopped by some people who built wooden blockades in the street," 33-year-old Zoure Sanate said from her bed in Cocody Hospital.

"They told us we must stay in the Plateau area until morning. None of us accepted to stay in Plateau until the morning for a celebration that ended at around 1 a.m.," she told the AP.

"Then came the stampede of people behind us," she said. "My four children and I were knocked to the ground. I was hearing my kids calling me, but I was powerless and fighting against death. Two of my kids are in hospital with me, but two others are missing. They cannot be found."

Another hospital patient, Brahima Compaore, 39, said he also was caught in the pile of people stopped by the roadblock.

"I found myself on the ground and people were walking on me," Compaore told the AP. "I was only saved by people who pulled me onto the sidewalk."

Set up by thieves?
Local newspapers are speculating that thieves set up the roadblocks so that pickpockets could steal money and mobile phones from the packed-in people.

Ouattara pledged to get answers. Some observers wondered why police did not prevent the tragedy.

Thierry Gouegnon / Reuters

People wounded from a stampede that occurred after a New Year's Eve fireworks display are seen in Cocody's Hospital in Abidjan, Ivory Coast, on Tuesday.

"The investigation must take into account all the testimonies of victims," he said Wednesday. "We will have a crisis center to share and receive information."

Ouattara also postponed the traditional New Year's receptions at his residence, which had been scheduled for Thursday and Friday.

Advocate: Incident was unsurprising
The leader of a human rights organization said that deadly incidents were predictable because the police and civil authorities had not taken adequate protective measures.

"The situation is deplorable," said Thierry Legre, president of the Ivorian League of Human Rights. "It is our first tragedy of 2013 but in 2012 we could already see possibility of such a tragedy because there are not adequate authorities patrolling our roads and waters."

More Africa coverage on NBCNews.com

He called on the government "to implement measures to avoid such tragedies in the future by reinforcing the civil protection system."

Just one night before the New Year's incident, there had been a big concert at the Felix Houphouet-Boigny Stadium where American rap star Chris Brown performed. That Sunday night event was for the Kora Awards for African musicians. No serious incidents were reported from that event.

Event intended to celebrate peace
The government organized the fireworks to celebrate Ivory Coast's peace, after several months of political violence in early 2011 following disputed elections.

Complete World coverage on NBCNews.com

In 2009, 22 people died and over 130 were injured in a stampede at a World Cup qualifying match at the Houphouet Boigny Stadium, prompting FIFA, soccer's global governing body, to impose a fine of tens of thousands of dollars on Ivory Coast's soccer federation. The stadium, which officially holds 35,000, was overcrowded at the time of the disaster.

More world stories from NBC News:

• Drug-resistant malaria threatens deadly global 'nightmare'
• From alcohol to kites: An A to Z guide to the Islamic Republic of 'Banistan'
• UK police: Attackers dressed as Oompa Loompas beat man
• Vatican launches swipe-card security system
• US sailors sue Japan's TEPCO for post-quake radiation exposure

Follow World News from NBCNews.com on Twitter and Facebook