(CNN) -- Four students were wounded when a gunman opened fire in the cafeteria of a suburban Cleveland high school just as the school day was beginning Monday, law enforcement officials said.
The suspected Chardon High School shooter -- believed to be a student, according to a school official -- was in custody, FBI Special Agent Scott Wilson told reporters.
Wilson declined to say how badly the injured students had been hurt.
"We just hope that they're OK," he said.
School administrators locked down schools in the city of Chardon, Ohio, about 30 miles east of Cleveland. and assured parents that all remaining students were safe.
Still, parents eager to retrieve their children hurried to school buildings, forming long lines as school officials checked identifications before releasing students. At one point, black-clad SWAT team members walked by parents waiting outside the middle school, enhancing what was a surreal scene for many.
"This stuff doesn't happen here at Chardon. Everybody's a little upset," said one parent who was preparing to pick up his daughter, a 10th-grader who had been evacuated to Maple Elementary School.
Despite initial reports that two people were involved, it appeared only one person was responsible for the shooting, Superintendent Joseph Bergant said.
"My understanding is there was one gunman," he said. Bergant said he believed the suspect is a student.
The shooting occurred around 7:40 a.m. just as school was getting started for the day, school board member Larry Reiter said. It happened inside the cafeteria, which is near the entrance to the school, he said.
It was unclear how the suspect was taken into custody.
School officials locked the high school down following the shooting.
One parent told CNN affilaite WKYC that her daughter had texted from a closet to tell her that there had been a shooting at the school, but that she was okay.
Chardon is a small city of about 5,100 people located 30 miles east of Cleveland. About 1,150 students attend the high school, which is next to Chardon Middle School and across the street from Maple Elementary School.
CNN's Melissa Gray and Chuck Johnston contributed to this report.