Updated

A 17-year-old girl is dead and two other people are injured after shots were fired Wednesday at an Alabama high school, investigators said.

Birmingham Interim Police Chief Orlando Wilson confirmed at a news conference that one female student, 17, died, and a male student, also 17, is in critical but stable condition.

A school employee was also injured, AL.com reported, but it's unclear to what extent.

The incident — which involved at least two shots fired — just before 3:30 p.m. at Huffman High School was initially reported as "accidental" but officials, but the police chief said investigators are investigating whether it was intentionally discharged.

"Right now we have a lot of unanswered questions. This should not happen in schools," Wilson said. "We are asking questions from the staff, the students, anyone who was in that area."

Authorities have, however, determined the shooting was not sparked by someone from outside the school. Officials declined to say who fired the weapon or identify what type of firearm it was.

In a statement, Birmingham City Schools said Huffman High was placed on lockdown and police were called amid the situation.

"Students have been released and police are actively investigating the circumstances surrounding the shooting," the statement read.

Birmingham Mayor Randall Woodfin said the deceased student would have turned 18 in about 30 days and was a senior "who had aspirations and dreams to be a nurse."

"We are not just talking about some person, talking about losing a part of our future. Our hearts are heavy. I think it's really important we find a way to mourn with this family," Woodfin said at the news conference.

The Associated Press contributed to this report.