The United Nations Monday rescinded its invitation for Iran to join this week’s peace talks on Syria in Switzerland in an attempt to sustain the effort to end a war that’s killed more than 100,000 people.

Iran “deeply disappointed” U.N. Secretary-General Ban Ki-moon by reneging on its private assurances that it supports the basis and goal of a 39-nation international peace conference scheduled to open Jan. 22 in Montreux, Ban’s spokesman Martin Nesirky told reporters Monday in New York.