A man has been arrested after two people were injured during a stabbing at Sony Music’s London headquarters.

The office, which is located on Derry Street, Kensington, saw firearm police and paramedics called out at around 11 am GMT. Despite early speculation, it is not believed any firearms were involved and it is not being treated as a terror incident.

A statement from police confirmed: “We are aware of an incident on Derry Street W8, police on scene including firearms officers and London Ambulance Service. At this time we believe two people are injured. Incident is ongoing.”

Journalist Simon Neville, who was outside Sony’s offices during the incident, told The Guardian, “Everybody starting pouring out and running towards the square around the back. Then I saw a young, white man with a red jacket being tackled by the security guards by the loading bay on Derry Street. He was shouting at them to get off. Once he was tackled they started bringing the shutters down. He has now been led away by the police.”

Trish Ellis, who works in Northcliffe House opposite Sony, told ITV News: “It started opposite our building in Derry St, usual sirens and racket but then we heard shouting, and more and more sirens. A few people came out, then armed police were going in six-plus at a time, and more and more of them, but they seemed to be keeping people in the building.

“Gradually they started to release people in tens, twenties, [and] a stretcher turned up with all the medical kit on it, but just stayed outside.

“A [helicopter] appeared, still loads of armed police running up and down, and then thankfully over the time it ended up much quieter with 10 armed police standing outside, at ease.

“[An] empty stretcher went away and, thank God in heaven, all seems calm again”.