Iran's invitation  has stirred controversy ahead of the highly-anticipated Syrian peace talks scheduled to commence Wednesday in the Swiss city of Montreaux, according to reports.
Agence France-Presse reported early Monday that French Foreign Minister Laurent Fabius has called on Tehran to "accept the creation of a transitional government [for Syria] with full executive powers" or forego attending the conference altogether.
"Participation in Geneva 2 is the explicit acceptance of this mandate. Under these conditions and in the interest of peace, it is clear that no country can participate in this conference if it does specifically accept this mandate," said Fabius in a statement.
Syria's main Western-backed opposition coalition also announced Wednesday that they will not attend the peace talks if Iran attends. Syrian National Coalition senior member Ahmad Ramadan told the Associated Press that the opposition will "suspend" its participation if Iran attends due to Tehran's "invasion" of Syria. 
The United Nations chief Ban Ki-Moon extended the highly-debated invitation to Iran early Monday after "lengthy" talks with Tehran's Foreign Minister Javid Zarif.
Iran is one of Syrian President Bashar Assad's top regional allies.