Syria's main opposition body, the National Coalition, will not attend peace talks in Switzerland scheduled for this week unless the United Nations retracts its invitation to Iran by 1900 GMT on Monday, a senior coalition member said.

Late on Sunday, UN Secretary-General Ban Ki-moon surprised the National Coalition when he invited Iran to the conference, dubbed "Geneva 2" and seen as the most serious international effort to end the near three-year conflict.

"We are giving a deadline of 1900 GMT for the invitation to be withdrawn," Anas Abdah, member of the National Coalition's political committee, told Reuters.

Abdah reiterated that the Coalition would accept Iran's participation only if it "publicly states that it is withdrawing its forces, committing to the Geneva 1 agreement in full and committing to implementing any results of Geneva 2."

Iran is the main foreign backer of Syrian President Bashar Al-Assad, and its attendance has been one of the most hotly debated issues in the run-up to the conference. - Reuters