At least 12 people died and some 100 were seriously injured in a stampede at a football stadium in El Salvador, the director of the civil defense agency, Luis Alonso Amaya, said late Saturday.

Police had earlier said that at least nine were killed in the stampede.

The injured were taken to hospitals near the Cuscatlan stadium in the capital San Salvador, with at least two in critical condition, the police tweeted earlier.

The match between FC Alianza and CD FAS was cancelled, as rescue workers scrambled to save lives.

The incident occurred as fans tried to enter the stadium. "It all started in the Sol General sector, where there was mass panic due to the excess number of tickets sold, affecting 500 people," Amaya said.

Local newspaper La Prensa Grafica reported that fans had complained the stadium was already overcrowded with many people waiting to get in.

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

Another fan, Sandra Argueta said children and elderly people were affected and the gate had to be kicked down "to get some air because there were a lot of people and we were suffocating."

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