Rescue crews who have looked for a missing Minnesota native in a rugged, difficult part of Yellowstone National Park in Wyoming are scaling back after 11 days without success, the National Park Service announced Wednesday afternoon.

Crews have centered their search for Austin King, 22, most recently around Eagle Peak, the highest point in the park and where King was last heard from on Sept. 17.

King, an employee at Xanterra Parks and Resorts in the park, went to Eagle Peak, west of Cody, Wyo., as part of a seven-day backcountry trip to climb in the mountainous area. Officials said he called family and friends from the summit in harsh weather. The search began after he was reported overdue for a boat connection back from the area Sept. 20. Crews found his personal items at a remote campsite near the peak. At one point, crews were analyzing his phone use in the hope of learning his whereabouts.

The search has involved more than 100 personnel, the Park Service said in a news release, including helicopters, dog teams, ground teams with spotting scopes, and a drone. Yellowstone and Grand Teton parks' teams had help from Park and Teton counties, too. The search has covered more than 3,225 miles from the air and on the ground, and now will move into a limited recovery phase.

"Although we will continue to hope for the best, I want to extend my deepest sympathies to Austin's family, friends and colleagues," Yellowstone Park Superintendent Cam Sholly said.

King's employer also issued a statement Wednesday after the park service update on the search.

NPS / Jacob W. Frank
Crews, at right, climb the southwest ridge of Eagle Peak.

"Austin is a fine young man and an excellent employee. He is sorely missed by so many of us at the park," said Mike Keller, Xanterra's vice president and general manager at the national park.

Attempts Tuesday to reach King's father, Brian King-Henke of Goodview, were unsuccessful. A post on his Facebook page acknowledged the change in the search:

"I will not give up until I get the call that says different of him being alive."