A school stabbing in Pennsylvania has left at least 20 students and one adult wounded after a 16-year-old went on a stabbing and slashing spree Wednesday at a high school close to the American city of Pittsburgh, South China Morning Post reported April 9.

Authorities said a 16-year-old American student went into a 30-minute rampage in the classrooms and hallways of a Pittsburgh high school, injuring at least 20 teenagers and an adult.

Trauma Medical Director at Forbes Regional Hospital Chris Kaufman told CNN that some of the said students suffered from life-threatening injuries.

The school stabbing at Franklin Regional High School in Murrysville reportedly began at 7:13 AM while the students of the school were arriving.

The bloody attack ended at around 7:45 AM after the suspect was taken into custody by authorities, according to Dan Stevens, a spokesman for Westmoreland County emergency management.

Stevens also identified the suspect of the school stabbing as a male student, adding that the 16-year-old was cornered by police officers, who immediately responded to the scene.

"Twenty students were injured, four of those students were flown from the scene," Stevens said.

Chief Medical Officer at Forbes Hospital Mark Rubino described the injuries of the victims who were rushed to the healthcare facility.

"The wounds were all knife wounds. Most of them were to the lower abdomen and they seemed to almost have a pattern," Rubino said adding that three patients have severe injuries and two of them were even in critical condition but have stabilized.

Meanwhile, the suspect of the school stabbing had injuries to his hand, Murrysville Police Chief Tom Seefeld said noting that he "is being medically treated."

Seefeld remarked that because the school's fire alarm was pulled during the school stabbing attack, more students were prevented from being harmed.

The victims of the bizarre attack are aged 14 to 17 and they were stabbed in "numerous classrooms and hallways," said Stevens.

A statement from the Franklin Regional School District was released, and it says that a "critical incident" had occurred. "All elementary schools are cancelled, the middle school and high school students are secure."

The school-stabbing suspect in custody is being interviewed by Murrysville police as of late, reports WTAE.