A riot outside of a major soccer match broke out in Egypt Sunday night. Authorities said the stampede and fighting between fans and police killed at least 25 people.
The riot comes just three years after similar violence left more than 70 people dead in 2012.
The stampede occurred before a match between Egyptian Premier League clubs Zamalek and ENPPI at Air Defense Stadium east of Cairo.
The Associated Press reports that Egypt's public prosecutor ordered an investigation, but that the initial cause wasn't immediately clear.
Security officials said Zamalek fans tried to force their way into the match without tickets, sparking clashes. Fans have only recently been allowed back at matches and the Interior Ministry planned to let only 10,000 fans into the stadium, which has a capacity of about 30,000, the officials said.
Zamalek fans, known as "White Knights," posted on their group's official Facebook page that the violence began because authorities only opened one narrow, barbed-wire door to let them in. They said that sparked pushing and shoving that later saw police officers fire tear gas and birdshot.
A fan who tried to attend the game told the AP that the stampede was caused by police who fired tear gas at the packed crowd.
The violence comes during a time of continuing unrest in Egypt amid bombings and attacks by Islamic militants. The police have also been under heavy scrutiny following the shooting death of a female protester in Cairo and the arrest of protesters under a law restricting demonstrations.