Two citizens of South Korea were killed Monday afternoon in a head-on crash on Wyoming Highway 220 near Pathfinder Reservoir, about a mile from the Carbon County line.

Soonyoung Lee, 46, was killed in the initial crash, and three-year-old Jaehyeok Seo died at the scene, according to a crash report from the Wyoming Highway Patrol.

Two others were injured. They have not been identified.

A Ford F-250 was eastbound on WY 220 at about 1:20 p.m., while a Ford Explorer was westbound. Near milepost 59, the F-250 failed to maintain its lane of travel and drifted across the centerline into the Explorer's lane, where the two vehicles collided head-on.

The F-250 came to rest blocking the eastbound lanes, while the Explorer ended up off the west side of the highway.

Lee, who was driving the Explorer, was killed in the initial crash despite wearing her seatbelt. The front right passenger in the Explorer survived and was taken by Life Flight to Wyoming Medical Center.

Seo, who was properly secured in a child seat in the back seat, died of his injuries at the scene.

The driver of the F-250 was pulled from the truck and taken by ambulance to Wyoming Medical Center.

Driver inattention and fatigue are being investigated as contributing factors.

Road conditions were dry, and weather was reported to be clear at the time of the crash.