HOOD RIVER, Ore. (AP) — The search resumed early Tuesday for a Polish military man who failed to return from an attempt to summit Oregon's Mount Hood.

Hood River County sheriff's Sgt. Pete Hughes says searchers plan to use a helicopter with equipment that can identify a signal from an international cellphone.

Hughes says 32-year-old Sebastian Kinasiewicz was reported missing Monday after he failed to return from Sunday's climb on the roughly 11,000-foot mountain. Crews found his car at a trailhead, but he remained missing after a daylong search Monday.

He carried warm clothing but was not equipped to stay out overnight — no sleeping bag or food. Hughes says conditions have been survivable.

Kinasiewicz has been in the United States for drone training at the Insitu company in Bingen, Wash.