A 17-year-old boy has been arrested for attempted murder after three people were injured at a school in Sheffield.

The force said the boy had been detained after reports of three people being injured at Birley academy on Wednesday morning.

It added: “Officers are at the scene after responding to reports of an incident involving a sharp object at the school on Birley Lane at around 8.50am. Two adults were checked over at the scene after suffering minor injuries. A child was also checked over after being assaulted.

“A 17-year-old boy has been arrested on suspicion of attempted murder and remains in police custody.”

In a email from the school to parents shared with the BBC, the headteacher, Vicky Hall, said there had been “an incident” but that “all staff and students are safe”.

Speaking from the school, one parent, Sophie Jones, told reporters she had received a text message from her daughter saying the school was “in lockdown, the lights had gone off, the doors were locked and she was hiding under her desk.

“It was really scary. I asked if she was joking because it seemed a really surreal situation. She has told me she was OK since then and I’m quite reassured that she is safe.”

Another woman said had come straight from work after her son alerted her about the incident.

“He said: ‘If you know what’s happening or have seen on social media just know I’m safe, there’s been a lockdown,’” she said.

“I will feel better once I see him; in these circumstances you are always going to worry even with the school telling you that your child is fine.”

A school spokesperson said: “This morning we went into lockdown as a precaution following an incident at the school. This was not a decision taken lightly but the safety of students and staff is paramount.

“All students and staff are safe. We are working closely with the police and will update shortly.’