The UN has revoked an invitation to Iran to attend a crucial peace conference on Syria this week amid strong opposition from the US to Tehran's participation and a threat by the Syrian opposition to boycott the talks. Under intense pressure, UN Secretary General Ban Ki-moon rescinded the invitation to Iran, issued only 24 hours earlier. The UN Chief said the talks will proceed without Iran's participation as Tehran as not ready to commit to the goals and basis of the conference. A statement issued by Ban's spokesperson here said that in a series of meetings and telephone conversations, senior Iranian officials had assured the Secretary-General that Iran understood and supported the basis and goal of the conference, including the Geneva Communique. "The Secretary-General is deeply disappointed by Iranian public statements today that are not at all consistent with that stated commitment. He continues to urge Iran to join the global consensus behind the Geneva Communique. Given that it has chosen to remain outside that basic understanding, he has decided that the one-day Montreux gathering will proceed without Iran's participation," the statement added. Previously, Ban and other UN officials said that Iran, as the main military backer of the Syrian regime, must be at the table for any meaningful talks about ending the nearly three-year-old Syrian conflict. Tehran had refused to accept a communique adopted by the major powers in Geneva on June 30, 2012 calling for a transition government in Syria. US officials had said Iran is prolonging the war and undermining chances for peace, and should not be allowed to sit at the table with diplomats from countries that are legitimately trying to end the fighting. Following the announcement that Iran would no longer participate, State Department Spokesperson Jen Psaki said the purpose of the conference is the full implementation of the Geneva communique, including the establishment by mutual consent of a transitional governing body with full executive authorities. The Syrian Opposition Coalition, which voted only the previous day to attend the talks after eight months of bitter debate, had issued a Monday evening deadline for the United Nations to rescind the invitation to Iran. Otherwise, the opposition group said, it would not attend the event.