PANAMA CITY -- The death toll from the nightclub roof collapse on Tuesday in Santo Domingo, the capital of the Dominican Republic, has climbed to 66, with 155 others injured, authorities confirmed.

Rescue operations are ongoing, said Juan Manuel Mendez, director of the Emergency Operations Center, describing the tragedy as one that has plunged not only the affected families but also the entire nation into mourning.

Dominican President Luis Abinader has declared three days of national mourning starting April 8 to honor the victims.

The collapse occurred during a party at the Jet Set nightclub in the capital in the early hours Tuesday. Jet Set is a well-known nightclub in Santo Domingo and often hosts live performances during the week.

Investigation is under way to determine the cause of the collapse.