Bridgeport Police, armed with tactical gear and a sledgehammer, surrounded a Washington Avenue apartment complex early Tuesday afternoon.
A short time later, they appeared to recover a long-barreled firearm that had been partially painted pink.
They also transported one person into an ambulance.
Neighbors described what they believed to be "a tense standoff" that involved a man shouting at police as the scene was locked down.
While officials provided no details, citing domestic violence laws, residents expressed gratitude for the prompt police response.
It was not immediately clear if anybody was arrested or hospitalized as of Tuesday night.