Tehran, June 1 -- Iranian Foreign Ministry spokesperson Esmaeil Baghaei on Monday said that ongoing exchanges between Tehran and Washington are taking place in an atmosphere of deep mistrust, accusing the United States of changing its positions and complicating efforts to reach an understanding, according to Iranian news agency ISNA.

Speaking at his weekly press conference, Baghaei said, "The negotiations began in the midst of severe mistrust and suspicion, and the exchange of messages is taking place in this atmosphere."

He added that diplomacy does not depend on trust between negotiating parties, but argued that shifting U.S. positions have slowed progress. "One of the difficulties of negotiating with the United States is the frequent...