A man has been arrested after two people were stabbed following a pickaxe attack at a London hospital, and one of the victims is in a life-threatening condition, police have said. The two stabbing victims are thought to be NHS maintenance staff members who work at Central Middlesex hospital, sources have told the Guardian. Gareth Browne, a building contractor at the site, said he saw the suspect wielding an axe and chasing two of his maintenance colleagues. Browne said: “He just came out of the side building waving a pickaxe about and chasing two lads. Those two lads scarpered. And he’s gone back into the hospital.” Later, Browne said he was told by another maintenance worker that the attacker stabbed two people inside the hospital. The suspect was arrested outside the hospital and was receiving treatment for life-threatening and self-inflicted injuries, the Metropolitan police said. One of the victims had life-threatening injuries, while the other did not, the force added. A source said both were being treated at St Mary’s hospital in Paddington, west London, which is the regional trauma centre for the area of the capital that includes Central Middlesex hospital. The incident was not currently being treated as terrorism-related, the Met said. The hospital was temporarily locked down but had reopened and would be operating services as normal, the force added. “The situation is under control and the two injured are receiving treatment,” a source said. Armed officers were seen running into the hospital just after 2pm. Footage on social media showed the officers swooping on the unit and shouting at passersby to move out of the way. The hospital is in the centre of the Park Royal business estate, on the border of two London boroughs, Brent and Ealing. It is managed by the London North West university healthcare NHS trust. A spokesperson for the hospital trust said: “We can confirm an incident took place at Central Middlesex hospital this afternoon. Police are on site and the hospital was temporarily locked down for a short period of time as a precautionary measure. “Working closely with the Metropolitan police, we have now reopened the hospital and services will continue as normal.” Leah, an administrative team leader at the hospital, said hundreds of patients and staff were evacuated. She said: “We were asked to leave, and by the time we came out, there was just loads of police, ambulances and all the people had been evacuated from the departments. “No one was screaming. Everyone walked out calmly, but you could tell they were shaken up. We were just scared because we didn’t know at the time if he’d been caught.” She added: “I just hope the people who are injured, come through.”