(CNN) -- A gunman barricaded the back door of an immigration services center with his car and burst through the front door on a shooting rampage, killing 13 people and then, apparently, himself, police said.
Four more were wounded in the attack at the American Civic Association in Binghamton, New York, and taken to hospitals in critical condition, according to authorities.
Police say they are still verifying the shooter's identity, but they believe that he was a man carrying a satchel of ammunition who was found dead of an apparently self-inflicted gunshot to the head, police Chief Joseph Zikuski said.
"It is our understanding he had ties to the civic association," Zikuski said.
A warrant is being obtained to search the suspected shooter's home in nearby Johnson City, another law enforcement source said.
In all, law enforcement removed 14 deceased people from the building and 37 survivors, Zikuski said, in what the city's mayor has called the "most tragic day in Binghamton's history."
At 10:31 a.m., authorities received a 911 call from one of two receptionists who were the first victims of the rampage. Watch witness describe his shock over incident »
She told police that the a man with a handgun shot her and her colleague before proceeding to a nearby classroom and opening fire, Zikuski said.
The other receptionist died, the police chief said.
While the gunman continued to fire, 26 others in the center hid in a boiler room downstairs, where law enforcement found them.
Zikuski hastened to add that two people who were led from the building in plastic handcuffs earlier in the day are not considered suspects.