Iranian Foreign Minister Mohammad Javad Zarif said Sunday that clinching a final nuclear deal with world powers is still "possible" despite a tough round of talks this week.

Iranian Foreign Minister Mohammad Javad Zarif said Sunday that clinching a final nuclear deal with world powers is still "possible" despite a tough round of talks this week.

"Agreement is possible. But illusions need to go. Opportunity shouldn't be missed again like in 2005," Zarif said on Twitter, referring to Iran's long-stalled dispute with world powers over its suspect nuclear program.