Iran’s Foreign Minister Mohammad Javad Zarif and U.S. Secretary of State John Kerry resumed crucial talks on Tehran’s nuclear program in Vienna as a self-imposed deadline for a deal expired.

The two top diplomats held closed-door talks at Palais Coburg Hotel in the Austrian capital on Tuesday.

Speaking after his meeting with Kerry, the Iranian foreign minister said he has a mandate to negotiate and clinch a final nuclear deal with the 5+1 group of world powers.

“I didn’t go [to Tehran] to get a mandate. I already had a mandate to negotiate and I’m here to get a final deal and I think we can,” Zarif said, according to Press TV.

After the 1.5-hour one-on-one meeting, Iranian deputy foreign ministers, Abbas Araqchi and Majid Takht-e Ravanchi, European Union deputy foreign policy chief Helga Schmid, U.S. Under Secretary of State for Political Affairs Wendy Sherman and Robert Maley of the U.S. National Security Council joined Zarif and Kerry.

Also present in the talks were director of the Atomic Energy Organization of Iran (AEOI) Ali Akbar Salehi and Hossein Fereydoun, Iranian President Hassan Rouhani’s top aide, as well as U.S. Energy Secretary Ernest Moniz.

------- Zarif says Iran accepts a ‘just deal’

Speaking to reporters upon his arrival in Vienna on Tuesday, Zarif said the talks between Tehran and the six world powers have reached a “very sensitive” phase.

Zarif returned to Vienna earlier on Tuesday after consultations in Tehran with the country’s leadership about the nuclear talks. He departed Tehran for Vienna with Salehi and Fereydoun.

Zarif had flown to Tehran on Sunday to consult on the ongoing talks, after meeting Kerry and other foreign ministers from the 5+1 group. He had initially planned to return to Vienna on Monday.

Zarif, who has himself suffered from recurring back trouble throughout the talks, immediately went to see Kerry, who is on crutches following a bicycle accident. A Western diplomat suggested, mostly in jest, that it might have been more convenient to organize the talks in a hospital ward.

“The only agreement that the Iranian nation will accept is a just and balanced deal based on the national dignity and the rights of the Iranian people,” Zarif asserted.

He added that the “political will” of the 5+1 group countries “will facilitate work on reaching an acceptable and lasting” agreement.

“I think the opposite [negotiating] side has also come to a reality that it will not be possible to reach a long-term agreement without a good agreement and without recognizing the Iranian people’s rights,” Zarif pointed out.

“All the Iranian officials have said they are ready for rational and wise negotiations and trade-off,” he said.

He emphasized that a final deal should be in accordance with the parameters of an agreement reached between the two sides in the Swiss city of Lausanne in April, saying, “In that case, it is possible to reach a resolution.”

------------ Continuation of talks for good deal

Meanwhile, a member of the Iranian negotiating team said on Tuesday that Iran and the six global powers would proceed with the nuclear talks within the next couple of days “in order to reach a good deal.”

“There is no word about the extension of talks,” the Iranian negotiator added.

He noted that Iran and the 5+1 countries have made “very little progress” on drafting the text of the final nuclear deal but they are advancing the work.

Following the meeting between Zarif and Kerry, the Iranian foreign minister started private talks with his Russian counterpart Sergei Lavrov.

The Russian foreign minister was set to meet with Kerry and German Foreign Minister Frank-Walter Steinmeier on Tuesday.

--------- IAEA to confirm Iran meeting key obligation under preliminary nuclear deal--------

Diplomats say that a UN nuclear agency will confirm that Iran has met a key condition of a preliminary nuclear agreement, changing a substantial amount of enriched uranium into a form that is difficult to use for nuclear arms, The Associated Press reported.

The diplomats said Tuesday that a report to be issued Wednesday by the UN’s International Atomic Energy Agency will show that Iran has complied with the obligation to render harmless the uranium it has enriched since November 2013.

---------- Negotiators miss deadline------

The negotiators between Iran and the 5+1 group now have an extra week or so before they face serious complications imposed by the U.S. Congress, which would undoubtedly be mirrored by the Iranian Majlis.

Diplomats have said the real deadline is not June 30 but July 9, the latest that the deal can be presented to the U.S. Congress if a mandatory review period before President Barack Obama can begin suspending sanctions is to be limited to 30 days. After that, the review will last 60 days, with growing risks that the deal could unravel.

And there is clearly still a lot of work to do. Even if every detail was agreed, diplomats say it would still take a few days to get it down on paper and reviewed by lawyers. And there are still issues that have evidently not been agreed.

White House spokesman Josh Earnest acknowledged that Tuesday’s deadline for a deal would be missed, saying “there are still some important unresolved issues.”

The sticking points could not be “resolved in the next 36 hours. It will require additional time, and that’s additional time that our negotiators will take in Vienna in pursuit of reaching an agreement that would prevent Iran from obtaining a nuclear weapon,” he told reporters in Washington, Reuters reported.

Even though Earnest spoke of imposing “the most intrusive set of inspections” ever agreed on a nuclear program, another senior U.S. administration official stressed global powers were not asking for access to every Iranian military site.

“The United States of America wouldn’t allow anybody to get into every military site, so that’s not appropriate,” the official told reporters.

“There are conventional purposes, and there are secrets that any country has that they are not willing to share.”

But the official said global powers had proposed a way forward as part of parameters agreed in Lausanne on April 2 “that we believe will ensure that the IAEA has the access it needs.”

------ Kerry says ‘too early’ to tell if Iran deal sealed -------

Kerry said earlier on Monday it was too soon to tell if a nuclear deal with Iran is possible.

“We’re just working and it’s too early to make any judgments,” Kerry told reporters in Vienna as he met with Yukiya Amano, the head of the International Atomic Energy Agency (IAEA), The Associated Press reported.

Asked about his lengthy one-on-one discussion with Zarif, Kerry said: “We had a good conversation.”

----------- Sticking to the parameters--------

In April, Iran and the 5+1 group agreed on the main outlines of a deal hoping to end a 13-year standoff over Iran’s nuclear ambitions.

But turning the 505-word joint statement agreed in April in Lausanne into a fully-fledged, highly technical document of several dozen pages, accompanied by several annexes, has proved challenging.

“It sounds easy, but it’s difficult,” German Foreign Minister Frank-Walter Steinmeier said Sunday.

---------- Years of negotiations---------

The nuclear talks have been going on for over 12 years. Iran’s original negotiating partners were the UK, France and Germany, a group known back in 2003 as the E3.

The talks gained greater momentum under the administration of President Rouhani, who tasked the Iranian Foreign Ministry – under Zarif’s watch – with handling the talks soon after assuming office in 2013.

Previously, Iran’s Supreme National Security Council (SNSC) had been in charge of the talks.