BINGHAMTON, New York - A lone killer armed with at least two handguns massacred 13 people at a citizenship center in New York state Friday before apparently shooting himself, police said.
The slayings took place on the main floor of the American Civic Association in Binghamton, 135 miles (217 kilometers) northwest of New York city.
The gunman, reported by media outlets to be of Vietnamese origin, had barricaded a car against the back door of the center to prevent escape. He then entered the front of the building and opened fire, apparently committing suicide soon after.
Dozens more people spent four hours cowering in the center's basement, waiting to be told by police that they were safe to leave.
Local police chief Joseph Zikuski said that there were "14 confirmed dead in the building" and that he had "very good reason to believe that the shooter is among the dead at the scene."
"We removed safely 37 people. Four people we removed are wounded. All four are listed in critical condition," Zikuski told a press conference.
However, he cautioned "by no means are we 100 percent sure" about the killer's body being among those at the building.
Zikuski said that the emergency call was made by the first woman shot by the gunman, a receptionist shot in the stomach but who pretended she was dead until she could make her escape.
"A lone gunman entered the building and immediately shot her and another receptionist. Unfortunately that (second) receptionist is now deceased. Then he went into another room and shot several more people."
Two handguns were recovered at the scene, he said.
President Barack Obama, on a visit to France, said he was "shocked and deeply saddened to learn about the act of senseless violence."
Many of those in the center, which helps people prepare for citizenship tests, were apparently of Vietnamese origin and did not speak good English.
New York state Governor David Paterson said victims were there to pursue "the American dream."
"There still is an American dream and all of us who are Americans will try to heal this very, very deep wound in the city of Binghamton," he said.
The outburst of violence apparently was over quickly, but hours of tension followed.
Zikuski said an emergency call was made at 10:31am (1431 GMT) by the receptionist as she lay on the floor wounded, listening to the gunman fire at others.
The police chief said he had "no idea what the motive is" and that the killer "just came in and shot her. I don't think there was any conversation."
Police swarmed into the area after the emergency call, with first units arriving in less than two minutes, he said.
"The gunfire had ceased by that time. There's no more shots fired."
However, it was unclear to police what the gunman was doing, or even how many there might have been, and elite SWAT police units took hours to comb methodically through the building.
Meanwhile, there were dozens of other people who had fled into the cellar and were talking to police by mobile telephone.
"We instructed them how to barricade the doors," Zikuski said. "They were very angsty."
Friday's carnage in New York state -- believed to be the deadliest such attack on record in Binghamton -- is the latest to rock small-town America, where many fiercely defend the legal right to bear powerful firearms.
On Sunday a heavily-armed man burst into a North Carolina nursing home killing eight people before being shot and wounded by a policeman.
Earlier this month, a 28-year-old unemployed man killed 10 people, including his mother and a toddler, in a shooting rampage through two counties in Alabama, the worst in the southern state's history.
In December, a man dressed as Santa Claus opened fire at a Christmas party being given by his ex-wife in Covina, California, killing nine people before shooting himself.
In October, an ex-convict opened fire with an assault rifle at a man and two children who had come to trick-or-treat at his home in Sumter, South Carolina on Halloween. A 12-year-old boy died of his wounds in that incident.
And in September, a mentally ill man shot eight people, killing six, in Alger, Washington a month after being released from prison.
An exasperated Paterson expressed his "profound outrage" at Friday's killings, and the series of deadly attacks that preceded them.
"When are we going to be able to curve the kind of violence so rampant that we can't even keep track of the incidents?" he said.
Friday's incident comes days before the second anniversary of a massacre at Virginia Tech -- the deadliest school shooting in US history in which 32 students and professors were shot dead by a student gunman -- and weeks before the 10th anniversary of the Columbine, Colorado school shooting.
The recent spate may be linked to the recession gripping the country, experts say.