Six people were injured, including several who were stabbed, in an altercation at a Washington state high school Thursday, authorities said, writes NBC.

Four were in serious condition and two sustained non-life-threatening injuries, a spokeswoman for the Tacoma Fire Department said earlier Thursday. All were in stable condition Thursday night, it said.

Several of the injured people were stabbed, Tacoma police told NBC affiliate KING of Seattle.

Officer Shelbie Boyd, a Tacoma police spokesperson, said they were injured during an altercation at Foss High School. Five of the people are students, including the suspect, and one is a security guard, Boyd said. As she added, the suspect, who has not been publicly identified, is in custody. She said it was unclear what prompted the altercation.

Emergency personnel responded to the school at 1:38 p.m., said the fire department spokeswoman, Chelsea Shepherd. Video from KING showed a large police presence outside the school, which was placed on lockdown, Boyd said.