Police and paramedics were called to Fonteyn Court in Hemlington, Middlesbrough just after 7pm on Monday (January 6).
Pictures seen by the Echo show four police cars at the scene with blue lights flashing and an ambulance parked outside a property.
The air ambulance was also called, and one person taken to hospital.
The nature of the incident is not yet known.
Cleveland Police has been contacted for further information.
A North East Ambulance Service spokesperson said: “We were called to an incident at a private address in Middlesbrough tonight (6 January) at 7:09pm.
“We dispatched one ambulance crew, one specialist paramedic and were supported by our colleagues at Great North Air Ambulance Service. One patient was taken to hospital for further treatment.”
A Great North Air Ambulance spokesperson added: “Our critical care team was activated at 7.22pm to an incident in Hemlington, Middlesbrough. We had two doctors and a paramedic respond on a critical care car and they arrived on scene at 7.31pm.
“Our team worked alongside the North East Ambulance Service (NEAS) to assess and treat a patient and they were taken to hospital by a NEAS road crew.”
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