The Lanterna Azzurra club was packed when, some local reports suggest, pepper spray was sacked inside the club in Corinaldo.
Six people were killed and around 35 injured in a stampede at a night club in Italy's Corinaldo near the coastal city of Ancona on Saturday, reported AFP.
About 1,000 people were in the Blue Lantern club in the town of Corinaldo on the Adriatic coast for a performance by Italian rapper Sfera Ebbasta, according to local reports.
A police official told Sky Italia TV that the teenagers were all aged between 14 and 16, while the woman was 39.
Twelve of the 35 injured were in serious condition, Mr Capocasa said.
Officials said people ran for the exits after someone sprayed a noxious substance at 1am local time (12am GMT).
Ancona Chief Prosecutor Monica Garulli told reporters at the scene: "The number of tickets sold is about 1,400, compared to a capacity of about 870" people.
The victims include five people under the age of 18 - three girls and two boys - and an adult woman who accompanied her daughter to the concert, media reports say. At one point, one of the side barriers collapses under pressure and sends several people falling on each other.
A teenager told ANSA he discovered that at least one of the emergency exits was locked when he tried to flee.
He said he did not have confirmation from survivors that the use of an irritating spray, like pepper spray, had set off the panic.
Firefighters had concentrated on giving first aid to survivors, stretched out on the road outside the club, before starting their investigation, he said.
"You can't die like this at 15", said far-right Interior Minister Matteo Salvini, promising to "find those responsible for these six broken lives, those who through wickedness, stupidity or greed turned a festive evening into a tragedy".