Several horses were killed in a Sunday evening crash on Interstate 40 in East Knox County, according to the Knoxville Police Department.

KPD said one of the trucks carried about 30 horses in the crash on I-40 East one mile west of the Strawberry Plains Pike exit around 8:38 p.m. Sunday. Several horses were also injured in the crash.

Members of the University of Tennessee Veterinary School and Animal Control Officers from both KPD and the Knox County Sheriff’s Office responded to the scene to begin treating the injured animals. KPD said authorities euthanized two horses on the scene due to the seriousness of their injuries.

Authorities were unable to transfer injured horses to another trailer along the interstate, so crews took the tractor trailer to the Mascot Stockyard so the horses could receive treatment.

KPD said two semi-trucks were traveling on I-40 East in the right lane when a flatbed semi that had stopped on the side of the road began to merge back into the lane of travel. The first semi-truck was able to change lanes to avoid hitting the merging truck, but the second semi-truck was unable to change lanes in time to avoid hitting the flatbed truck.

Three lanes of I-40 East were closed for about four hours Sunday night into early Monday morning.

Vehicles were backed up as far as Interstate 640.

TDOT crews cleared the crash around 1:30 a.m. Monday.

The investigation into the cause of the crash is ongoing.