"According to preliminary investigations, 19 died of stampede and suffocation in the disco hall," Daudi Siasi, Tabora regional police commander, told the Tanzania Broadcasting Corporation (TBC) on Wednesday.
"The stampede was caused by (a) commotion in the disco."
The incident occured in the Tabora region, 750km northwest of the commercial capital Dar es Salaam, where a large number of youths had gathered for Eid al-Fitr festivities marking the end of the holy month of Ramadan.
Saisi said several people were injured and taken to Tabora town's hospitals, where some were admitted and others were treated and then sent home.
"The town is in a sombre mood as a result the incident," he said, adding that police had launched investigations into what had caused the stampede.