Police confirmed a 14-year-old boy shot two boys, both 17, at W.R. Myers public high school. They would did not confirm local media reports that the shooter had been taken into custody.
They released no other details.
Mark Gregory, spokesman for the Lethbridge Regional Hospital, said the surviving victim was in surgery Wednesday afternoon.
Students on the scene told Lethbridge Herald reporter Craig Albrecht that the shooter, "walked in with a blue trench coat and a sawed-off .22 rifle and shot two kids."
Students at the school said the shooter was an unpopular ninth-grade student who had dropped out and was receiving home schooling.
"He said he's been really distressed," said Matt Anderson, one of 400 students at the school. "He didn't have very many friends."
The shooting came eight days after two students wearing black trench coats and belonging to a group that called itself the "Trench Coat Mafia," terrorized a school in Littleton, Colorado, fatally shooting 12 students and a teacher before killing themselves.
Taber is a farming community of 8,000 people about 186 miles southeast of Calgary.
"At first everybody thought it was a joke because we didn't think it could happen in our school in such a small town," student Raeanne Kunz said.
"When we found out it was real, everyone was pretty much hysterical. There was a lot of crying and scared kids. I was really scared."
Regan Valgardson, another Myers student, said she came across the shooter and one victim lying bleeding on the ground.
"When I walked out of the classroom I saw his gun right there," she said. "I asked the guy what he was doing. He told me to get lost."
Valgardson said the shooter was in her class last year.
"He wasn't very popular," she said. "Most kids were really rude to him. I always felt bad for him... I think that's one of the reasons. He said people were really rude to him."