A teenage girl has been arrested on suspicion of attempted murder after two teachers and a pupil were stabbed at a school in south-west Wales.

Dyfed-Powys police said they were continuing to investigate the incident after they were called to the Amman Valley school in Carmarthenshire at 11.20am.

Supt Ross Evans, the Carmarthenshire commander, said: “Emergency services immediately attended and the school was locked down for the safety of all on the premises.

“Three people – two teachers and a teenage pupil – have been taken to hospital with stab wounds. The family members of all those injured have been informed.

“A teenage girl has been arrested on suspicion of attempted murder and currently remains in police custody.

“I would like to reassure parents and the public that the incident has concluded, and pupils have now left the school.”

Evans said police were working with the school and other agencies to ensure support was available after the “very distressing incident”. He asked that people stop circulating footage of the incident on social media to avoid contempt of court and causing further distress. He added that police would be in the area in the coming days.