Buenos Aires, Argentina (CNN) -- A 13-year-old boy has been detained in Argentina in connection with a beating death Tuesday during the national Day of Spring celebrations, the official state-run news agency said Thursday.
The teen and a 24-year-old accomplice were identified by two witnesses as having used a piece of iron to beat a victim identified as Jonathan Villalba, the Telam news service said. The other suspect, who had not been apprehended, was identified as Pablo Ventosa, 24.
The teen suspect was not identified.
The beating death occurred in the city of Mercedes, in west-central Argentina.
In Buenos Aires, the nation's capital, at least 74 people were injured Tuesday during the annual celebration, and 20 of them required hospitalization, Telam reported Wednesday.
The injuries included stabbings, beatings and an alcohol overdose, the news agency said. The festivities marking the arrival of spring in the Southern Hemisphere were organized by the Argentine government at three parks in Buenos Aires.
Among those injured were two pregnant women who were robbed, a 3-year-old child who fell from an elevated surface and a 20-year-old woman who was in an alcoholic coma and had to be put on a breathing machine, Telam said. One gunshot victim also was reported.
The director of emergency medical services, Alberto Crescenti, said officials tended to 80 revelers in 2009 but there were more stabbings this year, "which denotes greater aggression," Telam said.
The festivities took place at three parks in Buenos Aires: Tres de Febrero, Costanera Norte and Roca. Argentina holds the celebration each year on September 21.
Most of the injuries at the Tres de Febrero Park occurred during a 90-minute period as a result of gang fights, Crescenti said.
Video of the events show mostly peaceful and playful gatherings, as many young people toss or kick balls around, sit and chat or engage in amorous embraces while a live rock band plays in the background.