Rescuers assist injured people outside a nightclub in Corinaldo, central Italy, early Saturday, Dec. 8, 2018.
Italian Prime Minister Giuseppe Conte told reporters that it appeared that only one of the nightclub's three halls had been open at the time.
In June a year ago about 1,500 people were injured in Turin after a firecracker sparked a stampede at a public screening of the Champions League final. Another eyewitness said a wall inside the club had collapsed in the melee.
Ancona police chief Oreste Capocasa said about 50 people were injured, 12 seriously.
Some 10 of those injured are in a serious condition, according to local media, with many suffering severe bruising or even broken bones. More than 1,000 people showed up to see Sfera Ebbasta, one of the nation's most famous young hip hop artists.
"One hypothesis was that overcrowding was a contributing cause", Carrozza said.
Witnesses described young clubbers racing for the exits at Lanterna Azzurra, in the town of Corinaldo, after an unknown substance was released into the crowd triggering a stampede.
Bobo Antic APRelatives and friends comfort each others outside the morgue in Corinaldo Italy Dec. 8 2018
He said he would cancel his promotional events over the coming days out of respect for the dead and injured.
The rapper said he didn't want to "express judgment" on those responsible but added he wanted everyone to "to stop and think how unsafe and stupid it is to use pepper spray in a discotheque".
Currently, firefighters are still trying to determine if any safety codes were violated, noting that when rescue crews arrived all doors to the venue were open.
Firefighters had concentrated on giving first aid to survivors, stretched out on the road outside the club, before starting their investigation, he added.
Italian President Sergio Mattarella promised to work tirelessly to determine "any responsibility and negligence".
Salvini concurred that it is "probably true that there were. more people inside than was permissible".
Teenagers were out due to the Immaculate Conception holiday in Italy in which high schools are closed.More news: Joe Gomez thanks Liverpool fans for their support after fractured leg