At least 33 people are dead and more than a dozen others wounded after a gunman opened fire ata Virginia college on Monday in what is being described as the worst campus shooting in U.S. history.

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An injured person is carried out of Norris Hall, where most of the fatalities occurred. 'At least 30 to 40 big shots' were fired in the engineering building, a student said. ((Alan Kim/Roanoke Times/Associated Press))

The suspected gunman took his own life at Virginia Polytechnic Institute and State University in Blacksburg, campus police Chief W.R. Flinchum told an afternoon news conference.

Police said they now know the identity of the gunman but are withholding his name for the time being. They said they did notknow his motive or whether he was a student at the college, which has a student body of about 26,000 in a town with a total population of only 39,573.

There were two separate shootings about two hours apart at opposite ends of the campus. The first took place at about 7:15 a.m. ET at West Ambler Johnston dormitory, a co-ed residence housing more than 800 students, and the second about two hours later at an engineering building, Norris Hall.

University president Charles Steger said Norris Hall had become a "tragic" and "horrific crime scene."

"Today the university was struck with a tragedy that we consider of monumental proportions," Steger said. "The university is shocked and indeed horrified."

Steger saidauthorities initiallybelieved the dorm shooting was a domestic dispute because police found a dead woman and man in one of the dorm rooms.

"We had no reason to suspect any other incident was going to occur,"Steger said.

Then at 9:25 a.m., police responded to calls of a second shooting at Norris Hall where they found a gunman had killed himself in a second-floor classroom after shooting dozens of students at that location.

Two weapons, which police declined to describe,were recovered and are now with a lab at the U.S. Bureau of Alcohol, Tobacco and Firearms to determine whether the shootings are related, Flinchum said.

Fifteen wounded peopleremain in several areahospitals, Flinchum said.

An off-campus man who knew one of the victims is a "person of interest" to police and has been co-operating,though he is not in custody, Flinchum said.

Gunman enters college room shooting

Derek O'Dell, a student wounded in the shooting, told MSNBC from a hospitalthat the shooter entereda room at Norris Hallthat had abouta dozen or sostudents and started shooting.

"He didn't say anything," O'Dell said. "He just shot and then left. Some of those hit were a lot more critical than me."

He said the shooter tried to get back into the room, but the students held the door shut.

"At first I thought it was a joke," O'Dell said. "You don't really think about gunmen just coming onto campus. But it became very serious, very quickly."

Trey Perkins, who was sitting in a German class in Norris Hall, told the Washington Post newspaper the gunman barged into the room at about 9:50 a.m. and opened fire for about a minute and a half, squeezing off 30 shots in all.

The gunman, Perkins said, first shot the professor in the head and then fired on the students. Perkins said the gunman was about 19 years old and had a "very serious but very calm look on his face."

"Everyone hit the floor at that moment," said Perkins, 20, of Yorktown, Va., a sophomore studying mechanical engineering.

"And the shots seemed like it lasted forever."

'It seemed so strange'

Erin Sheehan, who was also in the German class, told the student newspaper, the Collegiate Times, she was one of only four of the approximately two dozen people in the class to walk out of the room. The rest were dead or wounded, she said.

"It seemed so strange," Sheehan said.

The gunman "peeked in twice, earlier in the lesson, like he was looking for someone before he started shooting. But then we all heard something like drilling in the walls, and someone thought they sounded like bullets."

"That's when we blockaded the door to stop anyone from coming in."

She said the gunman "was just a normal-looking kid, Asian but he had on a Boy Scout-type outfit. He wore a tan button-up vest and this black vest, maybe it was for ammo or something."

"I saw bullets hit people's body," Sheehan said.

"There was blood everywhere."

As the shots rang out at Norris Hall, some students escaped through second-storey windows.

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About 26,000 students attend the college in Blacksburg, Va.: 'Blacksburg is a very small town, everybody almost knows everybody. It's going to be very bad and very sad in here,' one student said after the shooting.

A junior student named Josh, calling from campus, told the WDBJ news station in Virginia that he was inside Norris Hall when the gunman opened fire.

"We heard some loud banging, we weren't sure if it was construction or not, then we heard some screaming," he said.

"It didn't stop for at least two or three minutes," the student said, adding "at least 30 to 40 big shots" were fired.

"We all jumped out the window," he said.

'There were cops holding guns, shooting all over'

According to local television station WDBJ, high winds prevented helicopters from evacuating campus buildings.

Jamal Albarghouti, a student at the school, took video footage on his cellphone of the unfolding incidentuntil police asked him to move because he was too close to the scene. The sounds of gunfire can be heard on the video while police can be seen holding guns outside of a building.

"It was really terrible. There were cops holding guns, shooting all over," Albarghouti said. "You can't imagine how sad everyone here is."

He said he was not yet sure whether he knows any of the victims.

"Blacksburg is a very small town, everybody almost knows everybody. It's going to be very bad and very sad in here."

Locked down for hours at dorm

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Another injured person is carried out of Norris Hall. ((Alan Kim/Roanoke Times/Associated Press))

Another student, Aimee Kanode, said the shooting in the dormitory occurred on the fourth floor, one floor above her room. She said her resident assistant banged on her door about 8 a.m. ET to tell students to stay in their rooms.

"They had us under lockdown," Kanode said. "They temporarily lifted the lockdown, the gunman shot again.

"We're all locked in our dorms surfing the internet trying to figure out what's going on," Kanode said.

Student and dorm residentAlex Miller —who shot a video of two police officers outside the dormitory patting down a person who was later released —told CBC News it was "frightening" when the shootings were underway just one floor below him.

He said he was a bit scared about the prospect of returning to class, adding, "You don't know if one of your classmates could be one" of the victims.

Three local hospitals rolled out their disaster preparedness teams to deal with the victims.

Some students later questioned why the gunman was able to strike a second time. They bitterlycomplained that there were no public-address announcements on campus after the first burst of gunfire. Many said the first word they received from the university was an e-mail more than two hours into the rampage — about the time the gunman struck again.

Steger defended the university's handling of the tragedy, saying: "We can only make decisions based on the information you had on the time. You don't have hours to reflect on it."

'This is every parent's nightmare'

Craig Nessler, an associate dean at the school, said campus security personnel are armed and there are loudspeakers around the campus used to broadcast emergency messages — including in this case. He said the broadcast told students to seek shelter because of a shooting.

Nessler said he hopes extra counsellors, who have already been set up on campus, will help students cope with the terrible incident.

"This is every parent's nightmare, even if your child is not directly involved," he said.

The college closed all entrances to the campus, told faculty and staff to go home and cancelled classes for Monday and Tuesday. Officials said the campus itself would open Tuesday and a convocation to grieve the dead would be held at Cassell Coliseum.

The names of the victims may be released Tuesday, Steger said at the news conference.

Secondemergency closing in year

During a brief statement at the White House on Monday, U.S. President George W. Bush pledged federal support to local law enforcement and community officials.

"Schools should be places of sanctuary and safety and learning. When that safety is violated, that is felt in every American classroom," he said.

"Today our nation grieves with those who have lost a loved one."

In Canada, parliamentarians offered their condolences in the House of Commons.

"Such a senseless act leaves Canadians stunned and horrified," said Liberal MP Michael Ignatieff.

It was the second time in less than a year that the school, better known as Virginia Tech, has ordered an emergency closure of the campus because of a shooting.

In August 2006, the opening day of classes was cancelled and the campus closed when an escaped jail inmate killed a hospital guard and a sheriff's deputy involved in a massive manhunt just off the campus.

With files from the Associated Press