Iran has offered "rational proposals" in nuclear negotiations but "excessive demands" of the P5+1 world powers are likely to prevent agreement by the July 20 deadline, Tehran's foreign minister said on Thursday.
The five permanent members of the UN Security Council plus Germany are trying to secure a mammoth deal by next month to reduce in scope Iran's nuclear programme and ease fears the Islamic republic will get atomic weapons.
Iran denies seeking to make a bomb and wants punishing UN and Western sanctions lifted. Neither Israel nor the United States have ruled out military action to stop Iran from getting a nuclear weapon.
A difficult fifth round of talks ended in Vienna on Friday and the parties are due to meet again on July 2.
"Iran is ready for a resolution and made rational proposals," the official IRNA news agency quoted foreign minister Mohammad Javad Zarif as saying.
"But the excessive demands of the other party could prevent an agreement," he added. "At that time the world will know who was responsible for the deadlock in the nuclear negotiations."
Zarif had on June 20 said Iran and world powers are yet to find common ground on the main issues in the nuclear talks.
"We feel there are still maximalist stances on the other side, which I think should be dropped," Zarif had said.
Officials on both sides said the drafting process had begun, but that haggling over language concerning the thorniest problems was being put off until later.
The negotiations can be extended by up to six months beyond July 20, when an interim deal struck in November expires, but for now both sides were still aiming to get a deal by that date.
Negotiators have said the main sticking points are the timetable for a full lifting of crippling US and European Union sanctions, and the scale to which Iran would be allowed to continue uranium enrichment.