UPDATE 2:45 P.M.
Mayor Michael Nutter in another press conference around 2:30 today said 14 people were removed from the site—13 were transferred to area hospitals and one there is no comment on.
Multiple media outlets are reporting there are one or two dead, but fire officials told Metro that has not been confirmed.
Nutter and Commissioner Lloyd Ayers said it's still an active search and rescue site.
UPDATE: 1:30 P.M.
Fire Commissioner Lloyd Ayers said crews responded around 10:45 a.m. to the commercial 4-story former Forum Theater at 2136 Market Street, which collapsed onto the neighboring Salvation Army thrift store at 2140 Market Street, causing that property to partially collapse.
"Anyone who comes to this intersection knows – and I've come here a number of times – this is an active Salvation Army thrift store and it was open," Mayor Michael Nutter said, noting that at any point and time, it is impossible for officials to know how many customers and workers may have been inside the property.
All 12 people transported to area hospital are conscious and in stable condition, according to Ayers.
While on the scene, Metro saw another man being carried from the rubble on a stretcher as the surrounding crowd clapped.
There is no word yet on his condition.
Officials are reportedly looking for at least one more person believed to be trapped inside.
A Catholic priest and dogs with the police K-9 Unit were brought onto the scene around 12:30 p.m. this afternoon.
Mayor Michael Nutter said a perimeter has been established from 18th Street to Schuylkill River east and west and from the Benjamin Franklin Parkway to Walnut Street north and south.
"This is still an active search and rescue operation," he said this afternoon.
That area is closed to both pedestrian and vehicular traffic.
"We asking people to stay out of that area so our personnel can do dangerous and delicate work," Nutter said.
UPDATE: 12:30 P.M.
Mayor Michael Nutter said 12 people are in the hospital and Fire Commissioner Lloyd Ayers said two people are still trapped.
A four-story building and at least two other buildings collapsed at 22nd and Market Streets this morning, according to reports, with several people feared trapped and injured.
Emergency crews are pulling people out of the rubble, according to emergency radio reports. [embedgallery id=162882]
From someone who works across the street, crews were knocking down the adult shops and they believe it was a structural accident.
According to sources at the scene, the building that collapsed was a four-story residence with a Hoagie City restaurant on the first floor. The building is next to the Salvation Army thrift store. The thrift store does have damage to its facade.
Authorities are not allowing vehicles down 22nd Street at this time, according to emergency radio reports. A perimeter has been set up between the 2100 and 2400 blocks of Market Street.
Check back for more information, follow @metrophilly on Twitter for live updates.