At least 12 people died, and some 100 others were seriously injured in a stampede at a soccer stadium in El Salvador, Salvadoran authorities said Sunday.

It was the second deadly crush at a football match globally in six months, after a similar tragedy in Indonesia in October.

Civil Defense Agency Director Luis Alonso Amaya said the crush happened on Saturday evening when too many fans try to pack into one section of the Cuscatlan Stadium in the capital of San Salvador.

He said too many tickets had been sold for the match, between FC Alianza and CD FAS, which was quickly called off as a result of the stampede.

Carlos Fuentes, spokesman for the emergency services group Comandos de Salvamento, said they were treating more than 500 people.

Some 100 people in serious condition were taken to hospital, with some showing signs of asphyxia and other types of trauma, Fuentes said.

At least two of the injured were in critical condition, according to police.

"There were only two gates open in the whole stadium," one fan told the La Prensa Grafica newspaper. "The people outside wanted to force their way in, they all fell on us."

The newspaper described the panicked crowd on the sidelines of the first-division match as a "human avalanche."

Another fan, Sandra Argueta, described how another gate had to be kicked down "to get some air because there were a lot of people and we were suffocating."

Argueta said children and elderly people were caught up in the crush.

Survivor Sandra Guzman said she woke up in the hospital after fainting in the crush.

"A large crowd of people fell on me. I couldn't even breathe, they were choking me," Guzman told AFP news agency.

"The Salvadoran Football Federation deeply regrets the events that occurred at the Cuscatlan Stadium," the organization wrote on Twitter. "It also expresses solidarity with the relatives of those affected and deceased in this incident."

FIFA chief Gianni Infantino offered his "condolences to the families and friends of the victims who lost their lives after the tragic incidents that have taken place in El Salvador."

El Salvador President Nayib Bukele said the National Civil Police and the Attorney General's Office would conduct a "thorough investigation" into the tragedy.

He warned that "whoever the culprits are, they will not go unpunished."

Cuscatlan Stadium is one of the largest in Central America and has an official capacity of more than 44,000 fans.

The El Salvador stampede comes after a deadly crush year killed 135 spectators at a stadium in Indonesia's East Java in October.

Police had tried to fend off fans with tear gas and many panic-stricken victims were crushed or suffocated while trying to use closed or narrow exit doors.

An Indonesian police officer and two match officials were imprisoned for 12-18 months over the catastrophe.