(QHA) - UN Secretary-General Ban Ki-moon has invited Iran to participate in preliminary Syrian peace talks in Montreux, Switzerland, Radio Liberty reports. Ban said that Tehran had pledged to play a "positive and constructive role" if it were asked to participate in the talks, which are due to start on January 22. But a spokesman for Syria's main opposition group in exile said the Syrian National Coalition will pull out of the talks unless Ban retracts his invitation. According to Ban Ki-moon Iran is among 10 additional countries invited to attend the Montreux meeting on January 22. Two days later, formal negotiations between Syrian President Bashar al-Assad's delegation and Syrian opposition groups are scheduled to take place at UN headquarters in Geneva. Invitations to the one-day meeting of foreign ministers at a Montreux hotel had been subject to approval by the initiating states, Russia and the United States, but the two countries had been at an impasse over whether Iran, Assad's strongest ally, should attend.