One person was killed and another seriously injured following a single-vehicle crash Sunday morning on Highway 31 in Klamath County, according to Oregon State Police.

Two people were killed in separate crashes reported by Oregon State Police over the weekend, including a three-vehicle collision on Highway 97 in Klamath County where icy road conditions were a contributing factor.

Four people were killed in separate highway crashes across Oregon over a two-day period, with Oregon State Police investigating fatal incidents in Klamath, Deschutes, Josephine, and Columbia counties.

Two Klamath Falls residents were killed Wednesday in a rollover crash on Highway 140E after a passing attempt triggered a collision, according to Oregon State Police.

A wrong-way crash on I-5 near Grants Pass early Saturday left one person dead and two injured, according to Oregon State Police. Northbound traffic was impacted for about four hours during the investigation.

Oregon State Police are investigating two fatal crashes and one serious injury collision that occurred over the weekend in Malheur and Sherman Counties. Troopers are asking the public for information in one of the incidents, which left two people seriously injured.