US President Joe Biden said - Friday - that he believes that Iran is serious about negotiations over its nuclear program, but it is not clear to what extent, while Tehran confirmed that Washington has expressed its willingness to lift many of the sanctions it imposed on Iran during the Vienna nuclear talks, but Tehran demands With more.

The Al-Jazeera correspondent confirmed the end of the fourth round of the meeting of the Joint Committee of the Iranian Nuclear Agreement in Vienna, by agreeing to start technical talks.

When asked at the White House if he thought Iran was serious about the talks taking place in Vienna, Biden replied, "Yes, but to what extent and are they willing to do it is different. But we are still talking."

The White House said in a statement that it was ready to lift sanctions on Iran if it showed willingness to return to its commitments to the nuclear deal.

He added that returning to the nuclear agreement requires Iran to backtrack on a number of steps within the framework of its nuclear program.

The White House stressed that the indirect talks with Iran would be long, but stressed that Washington had touched a positive sign during the past weeks.

Technical discussions

On the other hand, the Iranian Foreign Ministry said that the technical committees in Vienna will continue the nuclear negotiations to draft the agreement.

She stated that the delegations participating in the Vienna meeting had reiterated their emphasis on striving to reach a conclusion as soon as possible.

On Friday, the fourth round of negotiations with the parties concerned with the Iranian nuclear agreement was held in Vienna, amid cautious optimism that an agreement would be reached before mid-June, while Tehran warned against turning the negotiations into a process of attrition.

Indirect negotiations began at the beginning of last April in the Austrian capital Vienna between the United States and Iran, with the Europeans and the rest of the signatories of the 2015 agreement, with the aim of preventing Tehran from developing a nuclear weapon.

Iran's demands

The chief Iranian negotiator, Abbas Araghchi, told state media that the United States has expressed its willingness to lift many of the sanctions it imposed on Iran during the Vienna nuclear talks, but Tehran is demanding more.

Araghchi said on state television, "The information that we received from the American side is that they are also serious about returning to the nuclear agreement, and so far they have announced their readiness to lift a large part of their sanctions."

He added: But this is not enough from our point of view, and therefore the discussions will continue until all our demands are met.

He explained that the sticking points in the negotiations are serious and fundamental, warning that the talks will not turn into what he described as an exhausting process.

The essence of the nuclear deal is for Iran to commit to taking steps to restrict its nuclear program, making it difficult for it to obtain fissile material for a nuclear weapon in exchange for relief from US, European and United Nations sanctions.

Tehran denies it is seeking nuclear weapons.

The Iranian negotiating team led by Araghchi arrived in Vienna earlier and held talks with the Director General of the International Atomic Energy Agency, Rafael Grossi.

Araghchi said - in statements to Iranian media, after his meeting with Grossi - that there is a good understanding between Iran and the International Atomic Energy Agency on various thorny issues.

He added that the two parties have deep cooperation, including even the issue of the expiry of the additional protocol between the agency and Iran.

It should be noted that this protocol stipulates, among its provisions, the installation of surveillance cameras at nuclear sites, and the right of IAEA inspectors to visit nuclear sites.

The additional protocol expires on May 21, which poses a problem if no agreement is reached before this date.

Final round?

Mikhail Ulyanov, Russia's permanent representative to international organizations in Vienna, said that the next - and possibly final - round of Vienna talks on re-implementing the joint work plan on the Iranian nuclear file will begin Friday.

Ulyanov added - in a tweet - that if the need arises, negotiators may decide to take a new break to obtain more instructions from their capitals.

In turn, Wang Kun, the Chinese representative in the Iranian nuclear negotiations in Vienna, said that the areas of consensus and disagreement became clearer after 4 weeks of negotiations.

He called on all parties concerned to focus on converting good political will into concrete measures, and to avoid exchanging accusations in order to push the negotiations forward.

Improve agreement

On the other hand, a US State Department official announced that Washington wants to talk with Iran about improving the nuclear deal after reaching understandings regarding it, adding that it understands what Iran must do to comply with the agreement, and also knows what it must do as well.

He emphasized that he does not intend to invent a new nuclear agreement, but rather to comply with the 2015 agreement.

He added that the previous US administration tried to pressure Iran for years, but this strategy did not succeed.

He pointed out that the last three rounds clarified more steps that should be taken to return to the nuclear agreement.

He pointed out that Washington had raised the issue of the Americans detained in Iran, but no agreement had been reached on them.

On Thursday, American, Iranian and European officials said that gaps are still wide between Washington and Tehran regarding the resumption of compliance with the Iran nuclear agreement signed in 2015, despite a US official saying that an agreement is possible within weeks if Iran takes a political decision to do so.

"Is it possible to see a joint return to compliance with the nuclear agreement in the coming weeks, or an understanding on mutual compliance? Answer: Yes, it is possible," the official told reporters, in a telephone briefing on condition of anonymity.

US Secretary of State Anthony Blinken said - in an interview with NBC - that Washington does not know whether Iran is ready to take the decisions required to return to compliance with the agreement.

An American proposal

A European diplomat said that Washington had put forward a comprehensive proposal that includes lifting sanctions on key sectors such as oil and gas and banking, and indicated a measure of openness to the easing of sanctions related to terrorism and human rights.

The diplomat - who requested anonymity - added that Iran had not shown any desire to curtail or destroy any experience it might have gained from working on advanced centrifuges.

A US official said that it is possible to revive the nuclear deal before the Iranian elections scheduled for June 18, but it falls again on Iran to make such a political decision.

The official added that it requires Iran to stop asking Washington to do more than what is included in the agreement, while Tehran seeks to do less.