A 16-year-old boy told Ansa that fans were dancing while waiting for the start of the show when the stampede erupted.
This comes as 1,500 people were injured in Turin after a firecracker sparked a stampede at a screening of the Champions League final in June previous year.
Fourteen of the injured were in serious condition, and some 40 others less seriously injured, he said. Local emergency services tweeted pictures of first responders treating injured patrons outside the nightclub.
Six people killed in Italian nightclub stampede
"Perhaps because of the dispersal of a stinging substance, boys flee by panic trampling". It quoted one teenager as saying that the emergency exit was blocked.
"You can not die like this at 15".
The footage filmed outside the packed Lanterna Azzurra club in Corinaldo, Italy, captures the chaotic atmosphere as a massive crowd tries to escape the building.More news: U.N. Fails to Pass U.S.-Sponsored Resolution Condemning Hamas
"I'm deeply saddened by what happened", Ebbasta said on Instagram.
Poggiali also said he didn't have any immediately confirmation about use of any irritating spray.
Pope Francis said during Saturday's Angelus prayers that he would pray for "the children and the mother who died last night.as well as for the injured".More news: Kendrick Lamar, Cardi B & Drake Lead the 2019 Grammy Nominations
Col. Cristian Carrozza, a chief investigator with Italy's Carabinieri, told The New York Times that the club sold about 1,400 tickets for the event, well over the venue's maximum legal capacity of 870 people.
Local media report around 120 people were injured, including 35 who were taken to hospital. Italian Interior Minister Matteo Salvini said there possibly was a "stink" that could have been ammonia or another substance.
Erika Pioletti, 38, died two weeks later after being left in a coma by the crush.More news: Trump expected to pick Heather Nauert for United Nations ambassador