U.S. Middle East envoy Jason Greenblatt said that one of the biggest challenges concerning the Mideast peace plan is making sure that Iran does not spoil the momentum.

After addressing the U.N. Security Council on reaching a peace deal between Israel and the Palestinians, he told reporters, “Even if I had a great peace plan, if we don’t figure out to make sure that Iran doesn’t spoil it, how much success are we really going to have?”

He added that peace between Israel and the Palestinians is Iran’s “worst nightmare.”

Greenblatt is convinced that both the Palestinians and Israelis want the decades of conflict to end, according to Fox News.

“In the last two-and-a-half years, I’ve met so many ordinary Palestinians,” he said. “They want better lives. I’m not saying they don’t want many of the aspirations that they have been promised. But they are just as talented as Israelis, just as eager to have successful lives like Israelis, and I believe that when they see the plan they will realize what lies ahead, what many benefits they can get from the plan. The Israeli side is the same. They just want to live safely and securely. They already have a great economy. They are frustrated, [and] they are skeptical just like the Palestinians.”

He added that he is confident the Palestinian leadership will eventually be more supportive of the peace process and see that the U.S. administration’s plans are in their interest.