This article has been updated.
At least 10 people were killed and seven others were injured when a gunman who demanded to know his victims' religions opened fire Thursday morning on the campus of Umpqua Community College in southwest Oregon, witnesses and authorities said.
The gunman was killed in a firefight with Douglas County sheriff's deputies, Sheriff John Hanlin said. Multiple law enforcement sources identified him to NBC News as Chris Harper Mercer, 26, but the sheriff wouldn't confirm that identity, saying he didn't want to "glorify" the man's actions.
"You will never hear me mention his name," Hanlin said Thursday night, because "he does not deserve it."
State Attorney General Ellen Rosenblum and other officials earlier had said 13 people were dead after the events near Roseburg, where the shootings were called in at 10:38 a.m. (1:38 p.m. ET). But investigators in Roseburg said they couldn't confirm that number, and law enforcement officials told NBC News it was likely that some victims were counted multiple times amid the confusion of the scene.
"At this time, we are reporting and can confirm 10 fatalities in the shooting," Hanlin said. "This number is the best, most accurate information that we have at this time."
No officers were injured, said Hanlin, who said: "It's been a terrible day."
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Investigators wouldn't say whether Mercer was included in the 10, and they said none of the victims would be identified for at least 24 hours. Law enforcement sources said that Mercer's connection to the college, where he wasn't a student, remained unclear.
Multiple law enforcement sources told NBC News that four weapons were recovered from the scene in Roseburg, in the southwest corner of the state about 60 miles south of Eugene — three handguns and a long gun similar to an AR-style rifle. Investigators also found several magazines for 5.56mm ammunition and a ballistics vest, one of the sources said.
"This has been a long, sad, tragic day at UCC," Rita Cavin, the college's interim president, said Thursday night. "And the thing we should take away from it is the power that love can bring to a community."
A visibly frustrated President Barack Obama — who has denounced the proliferation of guns in society after more than a half-dozen previous mass shootings — said "thoughts and prayers are not enough."
"It's not enough," he repeated. "It does not capture the heartache and grief and anger that we should feel, and it does nothing to prevent this carnage from being inflicted some place else in America next week or a couple months from now."
The FBI, the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives and the U.S. Marshals Service all joined numerous state and local agencies at the scene.
A parent of a student who was in the classroom where the shootings occurred told NBC News that the gunman asked at least "a few" people what religion they were. The parent asked that they not be identified.
Kortney Moore, an 18-year-old student, told the News-Review newspaper of Roseburg that she was in a writing class in Snyder Hall when her teacher was shot in the head. She also said the shooter told people to state their religions.
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Courtney Rennie, 23, second-year human services student, told NBC News: "I was walking into class, and I heard what sounded like a car backfiring. ... You don't even think that's somebody shooting a gun. I kept envisioning someone is going to come around the corner and and shoot the windows out."
Kenny Ungerman, a Navy veteran in his first year in the school's medic program, said he had just come out of a writing class at Snyder Hall and was talking to the National Guard recruiter when "we heard a gunshot."
"I it sounded like a handgun. It wasn't loud enough to be an assault rifle," Ungerman told NBC News. "Then I saw a guy with a handgun right outside — he was wearing jeans and a T-shirt. He was going toward the building, and he just disappeared into the building."
Ungerman said he heard people running and screaming, "He has a gun!" and "He's shooting!"
"I only saw him for a split second," Ungerman said.
Umpqua is a two-year school with about 3,300 full-time students and 16,000 part-time students. It started offering classes in 1961.
In a joint statement, the American Association of Community Colleges and the Association of Community College Trustees said called the shootings a "tragedy" and said they were committed to on-campus safety and security.
But "while campus safety is of the utmost priority, due to their open nature, college and university campuses are susceptible to these types of events," the organizations said.
Additional reporting by PETE WILLIAMS and TRACY CONNOR.
This article originally appeared on NBCNews.com.