3 injured in gas line explosion in Manhattan school

A gas line explosion during construction work at a high school in the US has injured three persons and severely damaged the school building, authorities said.
The explosion happened late last night at Manhattan in New York.
New York City Mayor Bill de Blasio tweeted that he was headed to the John F Kennedy High School in the Bronx neighbourhood to assess the scene.
"Keep 1st responders & victims in your thoughts," (sic) he said.
Authorities say three workers at the site of the school were injured when the gas line exploded at around 8 pm yesterday. The schools in the city are currently closed and will open for the the new session in September.

A report in CBS New York quoted energy company Con Edison as saying that the blast was a gas explosion.

At least three floors of the building were heavily damaged, officials told CBS2. Photos at the scene showed windows blown out and debris scattered in the vicinity of the building.
The Fire Department of New York said one of those injured was in critical condition, and the other two in serious, but non-life-threatening condition.
All three were taken to the burn unit at a local hospital.
Emergency workers , police and crews from the energy company have rushed to the scene to bring rescue efforts.

The school enrolls a total of 1,291 students, according to the Department of Education.