ISLAMABAD, Pakistan — The spokesman for Afghanistan's Taliban says they have suspended "mediation" with the United States to exchange captive U.S. soldier Sgt. Bowe Bergdahl for five senior Taliban prisoners held in U.S. custody in Guantanamo Bay.

In a terse emailed statement Sunday, Zabihullah Mujahed blamed the "current complex political situation in the country" for the suspension of what was considered the best chance of securing Bergdahl's freedom since his capture in 2009. It is the first official acknowledgment of indirect talks with the U.S. to free Bergdahl.

Bergdahl, 27, of Hailey, Idaho, was last seen in a video released in December, footage seen as "proof of life" demanded by the United States. Bergdahl is believed to be held in the border regions between Afghanistan and Pakistan.