A teenager described as a bullied outcast at his suburban Cleveland high school opened fire in the cafeteria Monday morning, killing one student and wounding four others before being caught a short distance away, authorities said.

A student who witnessed the attack from just a few metres away said it appeared the gunman was targeting a group of students sitting at a cafeteria table, and that the one who was killed was trying to duck under the table.

Panicked students screamed and ran through the halls after gunfire broke out at the start of the school day at 1,100-student Chardon High, about 48 kilometres from Cleveland. Teachers locked down their classrooms as they had been trained to do during drills, and students took cover as they waited for the all-clear.

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Chardon Schools superintendent Joseph Bergant speaks at a news conference Monday. (Tony Dejak/AP Photo)

One teacher was said to have dragged a wounded student into his classroom for protection.

The suspect, whose name was not released, was arrested near his car less than a kilometre away, the FBI said. He was not immediately charged.

FBI officials would not comment on a motive. But Danny Komertz, 15, who witnessed the shooting, said the gunman was known as an outcast who had apparently been bullied.

"I looked up and this kid was pointing a gun about 10 feet away from me to a group of four kids sitting at a table," Komertz said. He said the gunman fired two shots quickly, and students scrambled for safety. One of them "was kind of like hiding, trying to get underneath the table, trying to hide, protecting his face."

A Cleveland hospital identified the slain student as Daniel Parmertor, an aspiring computer repairman.

"We are shocked by this senseless tragedy," his family said in a statement. "Danny was a bright young boy who had a bright future ahead of him."

Parmertor's teacher at Auburn Career School had no idea why Parmertor, "a very good young man, very quiet," had been targeted, said Auburn superintendent Maggie Lynch.

At least one other victim was reported in critical condition.

Suspect's family offers 'sincere condolences'

Family members of the teenager suspected in the shootings say they are "devastated" by what occurred at the school.

In a statement issued to WKYC-TV in Cleveland Monday night, a lawyer representing the family of T.J. Lane offered "their most heartfelt and sincere condolences" to the family of Parmertor, adding that they are praying for the four other injured students.

Lawyer Robert Farinacci said Lane's family is trying to understand how the tragedy happened.

Even before official word of the attack was released, parents thronged the streets around the school as they heard from students via text message and cellphone.

By midday, officers investigating the shooting blocked off a road in a heavily wooded area several kilometres from the school. Federal agents patrolled the muddy driveway leading to several spacious homes and ponds, while other officers walked a snowy hillside. It wasn't clear what they were looking for. A police dog was brought in.

Teacher Joe Ricci had just begun class when he heard shots and slammed the door to his classroom, yelling, "Lock down!" to students, according to Karli Sensibello, a student whose sister was in Ricci's classroom.

Student heard moaning outside locked classroom

A few minutes later, Ricci heard a student moaning outside, opened the door and pulled in student Nick Walczak who had been shot several times, Sensibello said in an email. Ricci comforted Walczak and let him use his cellphone to call his girlfriend and parents, Sensibello said. She said her sister was too upset to talk.

Walczak and two other wounded boys were also students at Auburn Career School, the superintendent said.

Heather Ziska, 17, said she was in the cafeteria when she and other students heard popping noises in the hall. She said she saw a boy she recognized as a fellow student come into the cafeteria and start shooting.

She said she and several others immediately ran outside, while other friends ran into a middle school and others locked themselves in a teachers' lounge.

"Everybody just started running," said Megan Hennessy, 17, who was in class when she heard loud noises. "Everyone was running and screaming down the hallway."

Rebecca Moser, 17, had just settled into her chemistry class when the school went into lockdown. The class of about 25 students ducked behind the lab tables at the back of the classroom, uncertain whether it was a drill.

Text messages started flying inside and outside the school, spreading information about what was happening and what friends and family were hearing outside the building.

"We all have cellphones, so people were constantly giving people updates -- about what was going on, who the victims were, how they were doing," Moser said.

Anxious parents of high school students were told to go to an elementary school to pick up their children.

Chardon is a town of about 5,100 people.