UNITED NATIONS/ANKARA (REUTERS) - An unexpected last-minute U.N. invitation for Iran to attend a peace conference on Syria threw the talks into doubt on Monday, with the Syrian opposition saying it would pull out unless Secretary-General Ban Ki-moon withdraws his offer.
"We are giving a deadline of 1900 GMT (0300 am Singapore time) for the invitation to be withdrawn," Anas Abdah, member of the National Coalition's political committee, told Reuters.
Iran is the main foreign backer of Syrian President Bashar al-Assad and its presence has been one of the most contentious issues looming over the first talks attended by both Mr Assad's government and opponents, set to start on Wednesday in Switzerland.
Adding to dark clouds over the talks, Mr Assad said he might seek re-election this year, effectively dismissing any talk of negotiating his departure from power, his enemies' main demand.
Mr Ban's invitation appeared to catch Western powers off guard.
The United States and France both said Iran was not welcome at the talks unless it publicly backed an accord reached in Geneva in 2012 that calls for a transitional government for Syria.
"This is something Iran has never done publicly and something we have long made clear is required," U.S. State Department spokeswoman Jen Psaki said in a statement. "If Iran does not fully and publicly accept the Geneva communique, the invitation must be rescinded."
Syria's main political opposition group in exile - the National Coalition, which had contentiously agreed to attend the conference known as Geneva 2 only two days ago - said it would now pull out unless the invitation to Iran was withdrawn.
"The Syrian Coalition announces that they will withdraw their attendance in Geneva 2 unless Ban Ki-moon retracts Iran's invitation," it said in a Twitter post, quoting National Coalition spokesman Louay Safi.
Mr Ban said he had issued the invitation after Iran's foreign minister Javad Zarif told him Teheran agreed to accept the 2012 accord.
"Foreign Minister Zarif and I agreed that the goal of the negotiations is to establish by mutual consent a transitional governing body with a full executive powers," Mr Ban said. "He has assured me that like all the other countries invited to the opening day discussions in Montreux, Iran understands that the basis for the talks is the full implementation of the 30 June 2012 Geneva communique."
But Iran said it would attend the talks without having accepted any preconditions, apparently standing by its longstanding position.
"We have always rejected any precondition for attending the Geneva 2 meeting on Syria ... Based on the official invitation that we have received, Iran will attend the Geneva 2 without any preconditions," Iran's ISNA news agency quoted Foreign Ministry spokeswoman Marzieh Afkham as saying.
Russia, which has long lobbied for Iran to attend and criticised the opposition and the West for opposing Teheran's presence, said there was no point in a conference without it. "Not to ensure that all those who may directly influence the situation are present would, I think, be an unforgivable mistake," Foreign Minister Sergei Lavrov said.