The Turks, according to a Trump adviser, had cheated by “upping the ante” for Brunson. While the exact Turkish terms are unknown, Ankara has a long list of complaints, including the U.S. failure to extradite the Turkish citizen it considers responsible for a failed 2016 coup attempt, the U.S. investigation of a Turkish state-run bank for violating Iran sanctions, and attempts by Congress to prevent delivery of F-35 fighter jets that Turkey has already purchased.

Several U.S. officials and other people familiar with the situation insisted that there had been no misunderstanding of the terms of the deal.

“Turkey missed a real opportunity. Pastor Brunson is not a bargaining chip,” said a White House official, who like others spoke on the condition of anonymity about what has quickly become a major diplomatic incident with potentially wide-ranging ramifications.