Angola on Saturday announced an investigation into a stadium stampede that killed at least 17 and injured scores in what was described as the southern African country's worst football tragedy.
The government set up a commission to probe Friday's crush in the northern town of Uige, the national Angop news agency reported, with children among the victims.
Another body will be set up to help the families of the victims and assist in organising funerals after tragedy struck the domestic league match between host team Santa Rita de Cassia and Recreativo de Libolo on the opening day of the season.
"Several children have been killed," police spokesman Orlando Bernardo told AFP.
"There was a blockage at the entrance to the January 4 stadium," he said. "This obstruction caused multiple fatalities — 17 deaths, and there are 56 injured in the hospital."
Police said hundreds of fans had tried to enter the already packed stadium to see the match, causing a crush that pushed some people to the ground.
Many of the dead were trampled to death or suffocated.
"While the players were on the field, outside fans were trying to get into the stadium and a gate probably gave way to the pressure of the crowd causing several people to fall who were literally trampled on by the crowd," the Recreativo de Libolo club said in a statement on its website.
The club called it "a tragedy without precedent in the history of Angolan football".
Some witnesses said many fans did not have tickets to the match.
Sergio Traguil, the host side's coach, told the Diario de Noticias newspaper: "Nobody inside the stadium was aware of what was happening outside."
Images shown on Angolan television backed up the claim, showing thousands of spectators sitting around the pitch in a stadium with no stands.
Oil-rich Angola is slowly rebuilding its skeletal infrastructure, ravaged by decades of civil war.
The Portuguese news agency Lusa reported that the president of the host team said security forces were to blame for not properly controlling the crowd.
"There was serious police error in letting the people so close to the field," it quoted Pedro Nzolonzi as saying.
"Many of them did not want to pay and those who had tickets could not get in. Then the confusion began," he said.
"It is all the fault of the police. It was easy to avoid. They just need to extend the safety cordon."
Angola, ranked 148 in the FIFA world rankings, is a minor power in African football.
The country has been relatively closed to the outside world under the authoritarian President Jose Eduardo dos Santos who has ruled since 1979.
Football has a tragic history of stampedes and stadium deaths, often blamed on lack of crowd control, dangerous venues and spectator behaviour.
In 2009, poor crowd control in Abidjan caused 19 deaths before a 2010 World Cup qualifier between hosts Ivory Coast and Malawi.
A stampede at the Accra Sports Stadium in Ghana in 2001 resulted in 127 deaths.
At that game, supporters angered by their team's defeat threw projectiles and broke chairs. Police threw tear gas grenades, triggering a stampede.
Britain renovated its football grounds after 56 people died in a fire in a wooden stand in 1985 and 96 Liverpool supporters died in a crush during an FA Cup semi-final in 1989.