Grenades exploded on the pitch just moments before Rosario Central played bitter rivals Newell's Old Boys on Sunday afternoon, the latter club's Twitter account shockingly revealed. This is on the same day a fire broke out of Ajax's stadium hours earlier.
The lethal bombs were hurled on to the playing surface by supporters. It's unclear which set of fans committed the act and whether anyone was injured. The game was delayed due to the incident to fix the holes left in the pitch and conduct a security review.
The fixture is known as the Clasico Rosarino and has existed for more than a century. Rosario Central and Newell's Old Boys are both located in Rosario, a city in north-east Argentina. Other clubs play in the city, yet Rosario Central and Newell's are the two biggest.
"Teams are on the pitch," wrote Newell's official Twitter account shortly before kick-off. "A few bombs are thrown onto the pitch and explode as the teams lineup for their photos. There is now smoke filling one of the penalty boxes."
Newell's then shared a video of the incident, which showed a grenade exploding on the playing surface. Rosario Central's official Twitter account are yet to report it. Incredibly, the game was merely delayed by the incident and went ahead, with Newell's winning the clash 1-0.
Newell's are one of the most famous clubs in Argentina, winning six league titles and three national cups. The likes of Diego Maradona, Mauricio Pochettino and Gabriel Batistuta have represented the club. Lionel Messi played for their academy before joining Barcelona.
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Newell's have developed a cult following in the UK in recent years thanks to Marcelo Bielsa's four-year spell at Leeds. Bielsa started his managerial career at the Argentine club, spending a decade in charge of their youth team before getting the top job in 1990.
During his time at the helm, Bielsa won two league titles and lost the 1992 Copa Libertadores final to Sao Paulo on penalties. The renowned coach went on to become a hero in West Yorkshire, leading Leeds back to the Premier League in 2020.
Rosario Central, meanwhile, have won four league titles, six national cups and the now defunct Copa Conmebol - a continental competition organised between 1992 and 1999. Former Manchester United ace Angel Di Maria started his career at the club.
"Derby games are a nightmare back home in Argentina," said Di Maria in October 2014, shortly before the Manchester derby. "If you lost, it would be a case of not being able to go out, not just for two or three days, but two or three weeks!
"Everyone would really suffer if Rosario lost and didn’t want to show their faces to the fans until everyone had got it out of their system... I played in two Clasicos. I was on the winning side on one occasion - so obviously was very happy.
"But I also know what it’s like to lose and that feeling of having to stay in the house because of the disappointment of the fans. I know what it’s like when you have to keep your head down for a few days because we did lose one."