Ammon News - Agencies - Saudi Arabia said on Monday Iran was not eligible to attend the Geneva 2 peace talks on Syria, following the U.N. invite to Tehran to attend the conference later this week.

"Iran is not eligible to attend. Inviting any party to the Geneva 2 talks is dependent on their support of a transitional government,” a statement from the Saudi government read, broadcast by Al Arabiya News Channel.

“Iran has not voiced its support for a transitional Syrian government and has troops fighting alongside [Syrian President Bashar] al-Assad," the statement added.

The Syrian opposition threatened on Sunday to pull out from upcoming peace talks with global powers and the Syrian regime after the U.N. invited Iran to attend the conference.

U.N. leader Ban Ki-moon said Iran had pledged in the talks, due to start on Wednesday in the Swiss town of Montreux, to play a “positive and constructive role” in efforts to end Syria’s civil war.

But the announcement prompted the Syrian National Coalition to warn that it may withdraw from from the negotiations. It warned that it would not attend unless the invitation was retracted.

The Syrian National Coalition had only decided on Saturday to attend the conference and talks between Assad’s government and the opposition are due to start in Geneva on Friday.

Spokesman Louay Safi announced on the coalition’s Twitter account that the opposition group would withdraw “unless Ban Ki-moon retracts Iran’s invitation.”

The United States also said Ban should withdraw the invitation unless Iran, a key backer of Assad, gives “explicit” support to the conference aim of setting up a transitional government in Syria.

Following the dramatic series of events, Iran said it will attend Syrian peace talks this week in Switzerland but without preconditions, foreign ministry spokeswoman Marzieh Afkham told the official IRNA news agency.

"Based on the official invitation, Iran will participate in this conference without any preconditions," Afkham was quoted as saying.