Armed officers were seen responding to the incident in Northam on Tuesday night.
Police remain on the first floor of Kent House, in Kent Street, Southampton, amid a large cordon being in place.
Around three armed response vehicles were seen at the incident.
The air ambulance landed at the nearby park on Radcliffe Road.
READ MORE: Police in Kent Street, Southampton, as cordon is put in place - live
A woman on the estate has told the Echo she saw a man arrested and then released.
The 28-year-old said: "I saw loads of police cars and ambulance.
"There was tape around a few blocks. It was still being taped up when I went back out.
"They arrested someone but let him go very quickly.
"It's still under investigation and there is still a lot of police and investigators."
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