Police surrounded Lewisham High Street in London after they were called to what they said was a "disturbance" at around 10.45am on Monday, 10 February.
In a statement, the Metropolitan Police said officers attended the scene alongside the London Ambulance Service and the London Fire Brigade.
They were speaking to a man inside an address at the location and conducted enquiries to "establish whether anyone else is inside the property”.
“Lewisham High Street section of the A20 remains closed while the incident is ongoing,” police added.
