(CNN) -- A 14-year-old gunman shot students and teachers at a Cleveland high school, wounding four, and was then killed, the mayor told CNN affiliates WOIO and WKYC.

It was not known if police shot the gunman or if he took his own life.

The shooting victims include two adult men, 57 and 42 years old; and two teenage males, 17 and 14 years old, according to Cleveland Mayor Frank Jackson. A 14-year-old female hurt her knee in the chaos, he added.

Two students were taken to hospitals, said Andrea Jackson, press secretary for Cleveland's mayor.

One was taken out of the school on a stretcher but was conscious. Video Watch parents rush to the site of the shooting »

The teens are in "stable" condition, according to Jackson. He described the adults' conditions as "slightly elevated" above that of the students.

Witnesses told WKYC that the 14-year-old gunman was upset about being suspended for fighting earlier this week. He came to the school Wednesday with a gun in each hand and began firing.

Students said they took cover in closets after the school principal announced a "Code Blue" on the intercom.

The gunman was described by fellow students as "odd."

SuccessTech is a nontraditional high school, according to local school officials.

"Since it is a specialty school," it doesn't have "the typical population of a large high school," said Lisa Matthews of the superintendent's office.

It is a "school of choice" -- students have to apply to get in, said Ruthie Williams, also of the superintendent's office. She said classrooms are on the first and third floors of the four-story building and the rest contains the school district's administrative offices.

The academy describes itself on its Web site as a "small, nontraditional high school that provides a learning environment in which all student believe in their ability to succeed."

It adds that the curriculum is "problem-based" and "infused" with technology. E-mail to a friend E-mail to a friend