The last day of Electric Zoo was canceled on Sunday (September 1) after two festival goers died and at least four more were placed in intensive care.

The recommendation to cancel the final leg of the three-day EDM festival came from the city of New York. While a cause of death has not been determined in either case, according a press release issued by the city early Sunday morning, "both appear to have involved the drug MDMA," or Molly.

The New York Times reported that dead concertgoers were identified as 24-year-old Jeffrey Russ of Rochester and 20-year-old Olivia Rotondo of Providence, Rhode Island.

"The founders of Electric Zoo send our deepest condolences to the families of the two people who passed away this weekend," a statement read on the official EZoo website. "Because there is nothing more important to us than our patrons, we have decided in consultation with the New York City Parks Department that there will be no show today."

The statement on the city's website added, "The Electric Zoo organizers have worked with City officials to reduce health risks at this event, but in view of these occurrences, the safest course is to cancel the remaining day of the event."

Festival performers and other EDM artists quickly sent out their condolences on Twitter.

"RIP Jeffrey Russ & Olivia Rotondo you will be missed...sending my love to the families and friends who have to deal with this tragedy #EZOO5," Dillon Francis wrote.

"My thoughts goes out to families and the people who died at Electric Zoo in New York," wrote Sebastian Ingrosso, who was scheduled to perform Sunday along with Laidback Luke , who wrote, "Just heard the news. I'm so sorry New York! RT @EDMFacts: If you're partying, please remember to stay safe."

While he was able to take the stage before tragedy struck, Saturday performer A-Trak quickly shared his condolences, writing, "Really shocked to hear about the deaths at EZoo, especially because yesterday FELT positive over there. Thoughts are with the families."