Iran is criticizing the U.N. chief for rescinding his invitation to Tehran for the Syria peace talks in Geneva, calling the diplomatic about-face "deplorable."

Foreign Ministry spokeswoman Marzieh Afkham said on Tuesday that Ban Ki-moon's decision to withdraw his last-minute offer to Iran to attend the conference shows the U.N. chief came "under some pressure."

She says: "From our point of view, the withdrawal is deplorable."

Afkham says that Iran would expect Ban Ki-moon to explain the "real reasons" for withdrawing the invitation.

The invitation extended by Ban on Sunday put the talks in jeopardy, with the Syrian opposition threatening to boycott the gathering and the U.S. pushing for the rescinding of the offer to Iran, Syria's main regional ally.