When they met last month in New York, President Trump hailed what he called his “personal relationship” with Turkish President Recep Tayyip Erdogan and said the United States and Turkey were “as close as we have ever been.”

Erdogan called Trump “my dear friend Donald.”

Close observers of Ankara and Washington would have been ­forgiven for rolling their eyes. For the past several years, the ties between them have repeatedly frayed to near the breaking point, only to be temporarily patched. On Sunday, they snapped.

Following the arrest last week of Metin Topuz, a Turkish employee of the U.S. Consulate in Istanbul, the United States announced that it was immediately suspending the issuance of non-immigrant visas in Turkey. Ankara quickly responded with identical restrictions, suddenly upending the plans of countless Turkish and American tourists, students, busi­ness­peo­ple and others who did not already possess the necessary travel documents.

While the Turkish government provided no information about the Topuz arrest, the Daily Sabah, a pro-government paper, said in a Monday editorial that he was accused of “facilitating the escape” from Turkey of “known Gulenists” — followers of a U.S.-based Turkish cleric, Fethullah Gulen, whom Turkey accuses of being behind a July 2016 coup attempt.