Update 9:22 p.m.: Police have confirmed to Patch that a man was taken from the scene by ambulance to the Abington Memorial Hospital's psychiatric ward. Earlier in the evening, the man told his girlfriend that he intended to harm himself. The girlfriend then left the apartment and called police, authorities said.

The man also called a son, who lives in New York, and made similar threats, police said. It was not immediately clear why the man did not respond to police requests via loudspeaker, but he did make contact after officers used a flashbang device outside the residence. The subject was taken into custody shortly after, and was uninjured, police said.

Police confirmed the address as 907 Homestead Lane, Ambler, and said the male was in a third floor apartment. He also recently had hip surgery, police said.

County radio reports indicated that police found two shotguns and an unspecified third firearm in the man's apartment.

Update 9:11 p.m. An unidentified subject has been taken into police custody and is reportedly being placed in an ambulance that was standing by at the scene. Police officers at the scene could be seen exchanging handshakes.

The arrest took place just a few minutes after a county radio call to "deploy the bang." Following that radio transmission, a bright flash and loud explosive report were observed by a reporter at the scene.

Police are now inspecting the interior of the apartment.

Update 8:47 p.m. An unidentified woman on a megaphone, perhaps a police negotiator, is repeatedly hailing the occupant of the residence, addressing him as "Stan" and asking him to come out.

"We just want to know you're okay, Stan," she said several times.

Initial story below.

Officers from several law enforcement agencies have surrounded a residence on the 900 block of Homestead Lane, Ambler, where reports indicate an unidentified, possibly armed man has barricaded himself inside an apartment.

When Patch arrived at the scene at approximately 6:45 p.m., officers from at least three agencies, including Upper Dublin and Horsham Police departments, and a tactical emergency response team, were on scene. Roughly a dozen emergency response vehicles have blocked Homestead Lane from Bethlehem Pike, and are using the parking lot of the Montgomery County District Court as a staging area.

Several officers donned tactical gear, including helmets and automatic rifles.

A high-ranking officer of the Upper Dublin Police Department said information was not currently available as the operation is ongoing.

According to county radio reports, the target of the operation has turned off all the lights in his apartment. It was not immediately clear whether the individual possessed a weapon, whether authorities were in contact with the man, or why the police were seeking him.

A Bearcat armored vehicle operated by the Montgomery County Department of Public Safety arrived on the scene shortly after 8:00 p.m. County radio reports indicated that a police negotiator would be approaching the building in the Bearcat to attempt to contact the subject.

Residents of surrounding housing units have been asked to "shelter in place."

Check back with Patch as more information becomes available.