A nine-year-old Argentine junior motorbike rider has died after suffering serious injuries in a crash during a practice session at a weekend competition in Sao Paulo, event organizers said.

Lorenzo Somaschini was pronounced dead Monday at Sao Paulo's Albert Einstein Hospital, according to SuperBike Brazil.

Somaschini -- who hailed from the Argentine city of Rosario -- had been riding in a free practice on Friday for the Honda Junior Cup, one of the region's largest youth racing events, when he crashed in a curve at the Interlagos track in Sao Paulo.

Event officials said Somaschini received immediate medical attention and initially had stabilized, but his condition then worsened and he was moved to intensive care at the Albert Einstein hospital on Saturday.

"Everyone on the SuperBike Brazil team is appalled by this event and expresses our sincere sorrow to all of Lorenzo's family and friends," organizers said in a statement.

The Junior Honda Cup brings together riders between the ages of eight and 16 to race on modified motorbikes with specially adapted pedals and handlebars.

The bikes can reach speeds of up to 100 kilometers (about 60 miles) per hour.