Iranian Foreign Minister Javad Zarif appeared upbeat after marathon negotiations with U.S. Secretary of State John Kerry and European officials that lasted all night, though the negotiators’ work isn’t done yet. The talks were supposed to wrap up Tuesday but have been extended two days and counting.

Addressing reporters Thursday morning in Lausanne, Switzerland, Zarif said that “we have made significant progress, (but) we don’t have a final result yet.” He added that the parties expect to set the parameters for what will be part of a comprehensive agreement, which faces a June 30 deadline.

Later, as he was walking back to the hotel where the negotiations were being held, he told reporters that a media statement on the talks might be released.

Issuing a statement sounds like something less significant than the framework of understanding that the parties were aiming for.

“What we expect today is a statement and the fact that we have all reached common understanding on how to resolve the issues,” Zarif said. “But the agreement, a written agreement, is something that needs to be drafted by all participants and agreed upon in a multilateral process. And that would take, hopefully, three months, to finalize, and hopefully less.”

Asked if an understanding has been reached on all issues, Zarif replied, “that’s what we think we have, but nothing is agreed until everything is agreed.”

World powers — the United States, Russia, China, France, the United Kingdom and Germany — were examining the results of the overnight talks without Iran present, he said.

The talks, aimed at reaching a preliminary political deal on Iran’s nuclear program, blew past their initial, self-imposed deadline of late Tuesday as Iranian and U.S. negotiators struggled to find compromises on key issues.

But the negotiators have doggedly continued their work in Lausanne, trying to overcome decades of mistrust between Tehran and Washington.

The mutual mistrust has been a serious problem in the talks, Zarif said.

“I believe respect is something that needs to be exercised in practice and in deeds, and I hope that everyone is engaging in that in mutual respect,” he said.

‘A few meters from the finishing line’

“We are a few meters from the finishing line, but it’s always the last meters that are the most difficult. We will try and cross them,” French Foreign Minister Laurent Fabius said as he returned to the talks late Wednesday. “We want a robust and verifiable agreement, and there are still points where there needs to be progress, especially on the Iranian side.”

Iran wants swift relief from punishing sanctions that have throttled its economy. And Western countries want to make sure any deal holds Iran back from being able to rapidly develop a nuclear weapon.

It’s unclear what kind of accord might emerge from this round of talks — Iran appears to be resisting too many specifics, while the U.S. side wants to put hard numbers on key points.

Whatever it might turn out to be, the interim deal will need to be fleshed out into a full deal by June 30. Some of the thorniest issues could end up being left for that final phase.

But in the meantime, the Obama administration needs something solid enough it can sell to a skeptical Congress, which has threatened to impose new sanctions on Iran. The potential deal is also coming under sustained attack from Israeli Prime MinisterBenjamin Netanyahu.

21 questions on Iranian nuclear talks

CNN’s Elise Labott reported from Lausanne, and Jethro Mullen reported and wrote from Hong Kong. CNN’s Greg Botelho and Jim Sciutto contributed to this report.