While Iran was rewarded for limiting its nuclear enrichment program, the country's invitation to partake in UN-led Syria peace talks was revoked.
U.N. Secretary-General Ban Ki-moon on Monday rescinded an offer for Iran to attend Syria peace negotiations after Tehran said it didn't support the June 2012 political transition deal that is the basis for the talks.
In a brief statement by his spokesman — and under huge pressure from the U.S. — Ban withdrew the invitation, saying he was "deeply disappointed" by public statements today from Iran.
"He (Ban) continues to urge Iran to join the global consensus behind the Geneva communiqué," Ban's spokesman Martin Nesirky said. "Given that it has chosen to remain outside that basic understanding, (Ban) has decided that the one-day Montreux gathering will proceed without Iran's participation."
Ban said earlier that Iran's public statement that it did not support the 2012 Geneva deal calling for a transitional government for Syria was "not consistent" with assurances he had been given by Iran's Foreign Minister Mohammad Javad Zarif.
The Syrian Coalition – the main Western-backed organization working to oust Syrian President Bashar Assad – said it “welcomes the decision” to uninvite Iran as party to the peace talks.
The group had urged Iran to commit to withdrawing all “troops and militias” from Syria before being allowed to take part in negotiation.
The coalition also confirmed it will take part in the Geneva 2 conference, set to begin on Wednesday.
In a statement, the opposition said the conference should aim to establish a transitional government “full executive powers on all the State's institutes, including the army, intelligence and security forces, in which killers and criminals do not participate. “
Iran has supplied advisers, money and materials to the Syrian regime since the uprisings began in 2011.
With Iran out, the United States was hopeful all parties could refocus their efforts to end the Syrian civil war.
"We are hopeful that, in the wake of today's announcement, all parties can now return to focus on the task at hand, which is bringing an end to the suffering of the Syrian people and beginning a process toward a long overdue political transition," State Department spokeswoman Jen Psaki said in a statement released Monday evening.
NBC News' Andrea Mitchell and Reuters contributed to this report