ROME — At least six people were killed and about 40 others were injured, more than a dozen of them seriously, in a stampede early Saturday at a nightclub in central Italy where a popular rapper was scheduled to perform, officials said.

Panic broke out after midnight at the Lanterna Azzurra club in Corinaldo, a town near the city of Senigallia on the Adriatic coast. One unidentified witness interviewed by RAI News, the national news channel, said that pepper spray had been fired inside the club, setting off panic. But investigators did not confirm that.

Reports said that five of the people killed were minors, and that another was the mother of one of the young fans who had gone to the club to hear a concert by Sfera Ebbasta, an Italian rapper.

Luca Cari, a spokesman for the national fire department who was at the scene, said by phone that the situation had been “dramatic” and that it was still unclear how the events unfolded.