Emergency crews were called to a middle school in Charlotte, North Carolina, on Friday afternoon, just a day after a dozen students fell ill on campus.

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Officials with Charlotte-Mecklenburg Schools said symptoms reported at McClintock Middle School on Friday included nausea and vomiting along with dizziness and lightheadedness.

Twenty-three students and an adult were sickened, fire officials said. The students were released to their parents.

A mother leaving the school told WSOCTV that her child was sick for a second day in a row. She picked her up to take her to the doctors.

Another mother said she saw a teacher at the school who was sick, in addition to several children.

Paramedics responded Thursday afternoon to the middle school after 12 students reported feeling dizzy and lightheaded, school officials said.

WSOCTV was at the school Thursday and witnessed one student drop to the ground as he was led to an ambulance, while another student was taken on a stretcher.

A message was sent to parents after Thursday's incident that said the illness appeared to be heat-related, but school officials couldn't be sure.