UN Secretary-General Ban Ki-moon is "urgently considering his options" in light of the "disappointing conduct of some participants" involved in the Syria peace talks after he invited Iran to attend, his spokesman said Monday.
Martin Nesirky told reporters Monday that Ban "is dismayed" at the developments after he announced the invitation Sunday.
Nesirky says Iran, despite assurances, "has made a disappointing public statement" that suggests Iran doesn't accept the terms of this week's peace talks in Switzerland.
Senior US officials say the invitation must be withdrawn unless Iran fully and publicly endorses the formation of a transitional government for Syria that would pave the way for democratic elections.
Syria's main Western-backed opposition group says Iran must commit publicly by 1900 GMT (2:00 pm ET) to withdraw its "troops and militias" from Syria and abide by those terms, or the UN should withdraw the invitation.