After more than a year of indirect talks marked by frequent interludes, Iran and the US see an agreement aimed at salvaging the 2015 nuclear deal as closer than ever.

On Wednesday, Washington responded to Tehran’s comments on a draft proposal by the European Union that was submitted right after the latest round of talks in Austria’s capital by top EU diplomat Josep Borrell.

Borrell termed Iran’s response “reasonable,” and reports suggest that the US' response to Iran’s comments, which is currently being reviewed in Tehran, could help in clinching the deal.

While disagreements between Iran and the US appear to be narrowing, including on key sticking points, the standoff between Tehran and the International Atomic Energy Agency (IAEA), the UN’s nuclear watchdog, is now emerging as a roadblock.

"Give us the necessary answers, people and places so we can clarify the many things needed for clarification," IAEA Director General Rafael Grossi said Monday.

Grossi – who has made multiple trips to Iran since taking office in December 2019 – said Iran must answer the IAEA over uranium traces found at previously “undeclared sites” as part of the Nuclear Non-Proliferation Treaty (NPT) safeguards agreement.

"Dropping probes is not something the IAEA does or will ever do without a proper process. The key to this lies in a very simple thing: Will Iran cooperate with us?” he told CNN.

A day later, Sayed Mohammad Marandi, an adviser to Iran’s nuclear negotiating team, took to Twitter to declare that Iran’s nuclear program “will not be dismantled” and the IAEA probe must be dropped.

“No deal will be implemented before the IAEA Board of Directors permanently closes the false accusations file,” he wrote, referring to a resolution passed by the watchdog against Iran in June.

On Wednesday, Mohammad Eslami, the head of Iran’s Atomic Energy Organization, refuted reports that Iran has dropped its demand to shelve the probe as the parties to the nuclear deal gear up for a major breakthrough.

“We don't expect the director general of the agency (Grossi) to make statements that are exactly what the Zionist regime (Israel) wants,” Eslami told local media, echoing a claim made by many Iranian officials that the UN nuclear watchdog works “under the influence” of Israel.

IAEA-Iran standoff

The marathon negotiations between Iran and the P4+1 countries (Russia, China, the UK, France plus Germany) in Vienna since April last year have run parallel to the standoff between Tehran and the IAEA.

But tensions escalated after an anti-Iran resolution at the IAEA Board of Governors meeting in June, which prompted calls in Tehran for reduced cooperation with the UN watchdog.

The resolution, which followed the IAEA's quarterly report which criticized Iran for non-compliance with the NPT safeguards agreement, urged Tehran to fully cooperate with the UN watchdog body and give IAEA inspectors access to three "undeclared sites."

Iran's Foreign Ministry at the time termed it a "miscalculated and ill-advised" move and warned of a “firm and proportionate" response. Eslami said the UN nuclear body was "taken hostage" by Israel.

As the parties to the 2015 accord race to the finish line, the standoff between Iran and the IAEA threatens to play spoilsport, with both sides unwilling to budge from their respective positions.

“Almost 16 months after the talks began, Iran and the US, with the mediation of the European Union, are close to reviving the 2015 nuclear deal, but that doesn’t mean all gaps have been plugged,” Humayoun Zamaani, a Tehran-based strategic affairs analyst, told Anadolu Agency.

“Besides some issues that still need to be ironed out between Tehran and Washington, which I hope will take place in the coming days as the two sides discuss the EU draft proposal, the standoff between Iran and the UN nuclear agency needs to be resolved without further dilly-dallying,” he said.

Deal or no deal?

Iran has significantly ramped up its uranium enrichment activities from 3.67% stipulated under the 2015 nuclear deal to nearly 60% in response to the US withdrawal from the deal in 2018.

This has raised concerns in the West about possible military dimensions (PMD) of Iran’s nuclear program, putting Tehran and the UN nuclear agency on a collision course.

Nour News, affiliated with Iran’s top security body, on Tuesday criticized Grossi for “not seeing Iran’s goodwill” and “acting on the basis of reports” provided by Israel.

“With the continuation of this approach, the IAEA’s Rafael Grossi alongside ‘the Zionist regime’ have turned into main obstacles to finalizing talks,” the agency stated, insisting on resolving the PMD case.

On the other hand, Israeli Prime Minister Yair Lapid has expressed concern that the US and other parties are going to offer more concessions to Iran to reach a deal in Vienna.

Abolfazl Amouei, a senior lawmaker and member of the Iranian parliament’s foreign policy and national security committee, told Anadolu Agency that Iran is seeking a “beneficial and sustainable agreement” that will be “challenged” if issues between Iran and the IAEA are not resolved.

“Since the (UN nuclear) agency can disrupt the implementation of the agreement and Iran's benefits from it by making unsubstantiated claims, Iran insists that these remaining issues (between the two sides) be resolved before the implementation of the agreement,” he asserted.

Reiterating what other senior Iranian officials have said in recent months, Amouei described claims in the IAEA’s latest report on Iran as “political in nature,” calling for an agreement “with the political will of Western parties” and “without vandalism,” in an oblique reference to Israel.