SOUTH PARK - A child and an adult suffered life-threatening injuries when two SUVs collided head-on Sunday afternoon in this neighborhood south of Seattle.

Another adult and child also sustained less serious injuries in the crash, according to officers at the scene.

It's believed that he critically injured child was sharing a seatbelt with the other child, police said, but further investigation is needed to confirm that. The second child was also injured but less severely.

The two vehicles collided near the intersection of S. Cloverdale Street and Fifth Avenue S. Several ambulances, fire and police vehicles responded to the crash, which was treated as a "multiple casualty accident."

All of the injured people where in the same SUV, a white Yukon. The driver of the other SUV, who was the only occupant of the vehicle, was uninjured.

Emergency crews happened to be only a few blocks away at the time of the crash and arrived at the scene quickly.

Investigators said it appears the Yukon may have swerved into the oncoming lane of traffic, but that has not been confirmed.

More details will be provided as they become available.