One person has been killed and dozens more injured at the Alejandro Villanueva Stadium in Lima, Peru, according to football club Alianza Lima.

Hundreds of fans were attending a “flag-waving event” on Friday around the stadium, a day before a derby match between the home team Alianza Lima and local rivals Universitario de Deportes.

Officials are investigating the cause of the incident, which was not immediately clear. Initial reports suggested parts of the stadium’s wall had collapsed, but Alianza Lima ruled out any structural failures, as did a fire official.

The club offered condolences for the casualties, which included 60 injured according to media reports.

“We are fully and transparently collaborating with the competent authorities,” the club said in a statement on X, promising “total transparency” in helping to investigate what happened.

Peruvian health minister, Juan Carlos Velasco Guerrero, confirmed the death and said that 47 people had been hurt, with three people in critical condition.

Fire chief Marcos Pajuelo told news channel Canal N that based on initial assessments, the structure of the stadium had not been affected. “There are no collapsed walls or sections fallen into the pit,” he said.

“There hasn’t been any debris,” he added.

Earlier, the interior ministry had said on X that 40 firefighters responded to an emergency at the stadium “involving people trapped in a structure”.

The Peruvian professional soccer league said Saturday’s match will proceed as planned.

“We will continue to work closely with the clubs and authorities to promote safe environments both inside and outside the stadiums,” it said in a statement.

The league also highlighted its “commitment to the safety and wellbeing of all attended at sporting events.”

The Alejandro Villanueva Stadium, popularly known as Matute, was built in the 1970s and is located in the Matute neighbourhood of the La Victoria district in the Peruvian capital. It has a capacity of more than 33,900 seats.

There has been limited modernisation of the stadium since then, and it has remained a “fairly basic ground,” according to The Stadium Guide. In 2010, the wooden benches were replaced by plastic seats, and Alianza was reportedly exploring ways to upgrade the stadium, including increasing the capacity to 40,000 spectators, as well as plans for a new arena that can hold 60,000.