"I can't be confident it is imminent.. a few months ago we thought we were pretty close as well," Malley said at the Doha Forum international conference, Reuters reported.
The US envoy claimed that the sooner an agreement is reached, the more faithfully they implement it.
The United States will maintain sanctions on Iran’s Revolutionary Guards even if there is a deal to limit the country’s nuclear program, Malley said, according to Al-Arabiya.
Earlier on Sunday at the Doha Forum, Kamal Kharrazi, head of Iran's Strategic Foreign Relations Council said that a nuclear deal is within reach but could only happen if the United States showed political will.
Kharrazi said it was vital for Washington to remove the foreign terrorist organization (FTO) designation against Iran's elite Islamic Revolutionary Guard Corps (IRGC).
"IRGC is a national army and a national army being listed as a terrorist group certainly is not acceptable," the former Iranian foreign minister said.
The Iranian Foreign Minister Hossein Amir-Abdollahian said on Sunday that the Iranian side has reached an agreement with three European countries on a draft text that needs to be finalized, calling on Washington to take practical steps to lift the sanctions on Iran.
MP/PR