MIAMI (AP) — Officials say up to four people were injured when large lighting equipment being set up for the Ultra Music Festival collapsed in downtown Miami.

Fire rescue workers responded to Bayfront Park Thursday evening and took victims to a nearby trauma center. The Miami Herald ( reports that the accident apparently occurred as a stage was being erected. The annual outdoor electronic music festival is set to begin Friday and run over two weekends.

It wasn't immediately clear if those injured were workers or how badly they were hurt.