Crews searching for two missing hikers in Wrangell-St. Elias National Park and Preserve found two gear-filled backpacks and other camping items along a 7-mile stretch of the Sanford River, the National Park Service said Monday.

The agency has led the search for the hiking couple, from Missouri, after they failed to meet their air taxi pick-up Wednesday at the Dadina River.

"From the evidence we have so far, it appears they tried to cross the river and didn't make it, but we're piecing that all together still," said Margie Steigerwald, spokeswoman for the park.

The Park Service has not released the hikers' names at the family's request, but will do so at a later time, Steigerwald said early Monday.

"Although no people have been found, the identification in each of the backpacks matches the names of the missing hikers," the agency said in a statement.

The backpacks were discovered as river levels on the Sanford River dropped Friday and Saturday, producing dry river channels.

Searchers also spotted footprints near the Sanford Glacier that matched the tread of a boot found a mile down the river.

The couple had planned to hike six days from the Sanford River, crossing the Dadina Plateau and ending at the Dadina River.

Their gear was found near the location where the couple was dropped off by an air taxi service June 22, the agency said.

"An intensive aerial and ground search on Saturday yielded a few more items but no additional sign of survivors," the Park Service said.