Police have said there are no other known gunshot victims.
Knoxville Mayor Indya Kincannon visited the wounded officer in hospital and told reporters outside that he was conscious and in good spirits. "That's why we are focusing our efforts to protect the innocent, protect the school, protect the children and students and staff".
One person is dead, another detained, and an officer with the Knoxville, Tennessee Police Department was injured with non-life-threatening injuries after a shooting Monday afternoon at a high school in Tennessee.
"Upon approach of the subject, shots were fired".
The spring semester for Knox County Schools, Austin-East Magnet High School's district, began on January 5. It was not immediately clear if either attended Austin-East Magnet School. "We are gathering information about this tragic situation and will provide additional information as soon as possible", Knoxville schools superintendent Bob Thomas said on Twitter.
The shooting, which unfolded about 3:15pm on Monday (local time) at Austin-East Magnet School on the east side of Knoxville was the latest episode of gun violence in the United States since mid-March.
Students not involved in the incident have been released to their families.
Police established a reunification site for families of the students at the baseball field behind the school.
The school, which had opened its classrooms after pandemic lockdowns, switched to remote learning for a few days in February so that students could grieve the deaths of two 15 year olds and one 16 year old, WBIR-TV News reported.
The nation has seen series of mass shootings in recent weeks, including eight people killed at three Atlanta-area massage businesses on March 16 and 10 people killed at Colorado supermarket on March 22.
It said the Tennessee Bureau of Investigation, a state-level department, would lead the probe into what happened.
Police say there are multiple victims, including an officer.
Tennessee governor Bill Lee described the shooting as "very hard and tragic".
The law, which does not apply to long guns, will take effect July 1.