Eight children were hospitalized Tuesday after they began experiencing “seizure-like symptoms” while participating in a free church choir performance in Massachusetts, according to WCVB.

Firefighters responded to St. Paul’s Parish in Cambridge, Massachusetts, around 7 p.m. after receiving a call that a child was having a seizure, WCVB reported. Seven other children soon experienced “seizure-like symptoms.” All eight children were transported to local hospitals, with some of the children indicating they’d felt ill during the performance due to an odor, WCVB reported.

Cambridge Fire Chief Thomas Cahill discussed the incident with WCVB, describing it as “somewhat unusual.”

“This was somewhat unusual. It was a routine medical call that quickly escalated into transporting eight children to the hospital. Not common,” Cahill told the outlet. Hazardous material and rescue teams cleared the building and reported zero readings. The building was ventilated, and no one else who attended the concert was affected, according to WCVB.

The children ranged between 11 to 13 years old and were part of the Children’s Choir of Île-de-France, USA Today reported. The free concert at St. Paul’s Parish was part of their U.S. tour, the outlet indicated.

St. Paul’s Parish confirmed the choir group was performing a free concert via a July 22 post shared to its Facebook account.

“The Chœur d’Enfants d’Île-de-France will offer a free concert at St. Paul’s as part of their 2025 US tour. Founded in 1970, the youth choir has travelled extensively and performed with some of the world’s top conductors and soloists. The concert will feature [an] exciting mix of sacred and secular repertoire, as well as popular French songs,” the post read. (RELATED: ‘Three Seconds’: Surf Instructor Describes Having Limb Severed In Freak Train Accident)

What caused the children’s apparent illness remains unclear, Fox News reported.