Representatives of Iran and diplomats from Britain, China, France, Germany and Russia are gathering at the Palais Coburg hotel in Vienna on Monday to begin two days of talks aimed at salvaging the 2015 international nuclear agreement officially known as the Joint Comprehensive Plan of Action or JCPOA.    

The United States is taking part in the talks indirectly, with diplomats from the other countries acting as go-betweens.

The negotiations are aimed at bringing Iran back into full compliance with the agreement and paving the way for the US to rejoin it.

The new round of talks comes after a hiatus triggered by the June election of hard-line cleric Ebrahim Raisi as Iran's president.

On Monday, the Iranian Foreign Ministry said its delegation was in Vienna "with a firm determination to reach an agreement and is looking forward to fruitful talks."

"If the other side shows the same willingness, we will be on the right track to reach an agreement," said ministry spokesman Saeed Khatibzadeh.

Conditions not favorable for a deal?

The 2015 JCPOA deal imposed strict curbs on Iran's nuclear program. In exchange, world powers promised Tehran they would lift some of the array of economic sanctions imposed on the country. 

But in 2018, President Donald Trump unilaterally withdrew the US from the deal and began slapping new sanctions on Iran.

Tehran then retaliated by exceeding limits on its nuclear activity as laid out in the deal.

In recent months, Iran has started enriching uranium to unprecedented levels and has also restricted the activities of inspectors from the International Atomic Energy Agency (IAEA), the UN watchdog charged with monitoring Iran's nuclear facilities.

After his trip to Iran last week, IAEA Director-General Rafael Grossi said "no progress" had been made on issues he raised during a visit designed to address bones of contention between the agency and Iran.

The agency's nuclear inspectors remain unable to fully monitor Iran's program after Tehran limited their access in February.

One particular area of concern for the IAEA is a centrifuge-components manufacturing unit in Karaj, near Tehran.

The IAEA has not had access to the site since its surveillance cameras there were damaged by an "act of sabotage" in June — Iran has accused archrival Israel of carrying out an attack on the site.

Iran continues uranium enrichment

Last week, the IAEA reported that Iran had significantly increased its stockpile of highly enriched uranium in recent months — to levels exceeding those allowed under the JCPOA.

According to Iranian government data from early November, Tehran possesses about 25 kilograms (55 pounds) of uranium enriched to 60% purity.

That puts it well outside the terms of the nuclear agreement, which allows the country to hold a limited amount of uranium enriched to 3.67% purity, with a maximum limit of 300 kilograms.

According to a report released by the IAEA this month, Iran possesses 17.7 kilograms of uranium enriched to 60% purity. Experts believe Tehran, if it wants, could enrich uranium to about 90% in a matter of months, paving the way for it to have enough weapons-grade uranium to build a nuclear bomb.

The US won't 'sit idly'

"I see Iran's recent steps in expanding its nuclear program and its lack of cooperation with the IAEA as part of a dual strategy," Younes Zangiabadi, executive vice president of the Canadian think tank Institute for Peace and Diplomacy, told DW.

"On the one hand, this is a reaction to the alleged Israeli acts of sabotage against the Iranian nuclear facility in June, which Tehran says led to the dismantling of the cameras installed by the IAEA. On the other hand, it is an approach designed to give the country more leverage at the negotiating table," he said.

Iran claims the cameras and surveillance technology installed by the IAEA were used to sabotage its nuclear program.

Tehran wants to demonstrate that such acts of sabotage are not only ineffective, but also increase the cost and effort for foreign countries to gain access to and transparency over Iran's nuclear program, Zangiabadi said.

Washington, meanwhile, has stressed that it won't "sit idly" by if Iran gets too close to making a nuclear weapon.

Last week, US Special Envoy for Iran Rob Malley said Tehran's attitude "doesn't augur well for the talks."

"If they start getting too close, too close for comfort, then of course we will not be prepared to sit idly," Malley told National Public Radio (NPR) in Washington.

Iran argues the US should take the lead in finding a diplomatic solution as Washington had unilaterally withdrawn from the international agreement.

Tehran has demanded the lifting of all US sanctions, in addition to assurances that Washington will stick to the nuclear agreement in the long run.

US President Joe Biden has signaled that he wants to rejoin the deal but has so far been unwilling to agree to such pre-conditions.

Furthermore, the Trump administration imposed sanctions on Iranian organizations and individuals on the grounds of "supporting terrorism" and not related to the nuclear program. It makes it difficult for Biden to lift such sanctions and any proposal to withdraw them would likely face opposition from Republicans in the US Congress.

Interim agreement — a way out of the impasse?

A revival of the JCPOA is very unlikely in the current political climate, Zangiabadi said.

But a possible way out of the impasse is for the US and Iran to reach an interim agreement, he added. 

"This can be a solution to address the most important concerns of both sides in the short-term and to buy more time for negotiations on a version of the JCPOA that can be achieved later and is viable in the long-term."

The Middle East expert also believes Biden has enough political leeway to provide sanctions relief for Iran and release Iranian funds frozen in banks as part of the US sanctions. 

Kourosh Ahmadi, a former Iranian diplomat, shared a similar view during an interview with the Iranian newspaper Etemad. It would be up to diplomats to work out the details of such an interim agreement, Ahmadi said, adding: "Once the details have been worked out and the benefits for Iran become clear, given the current economic situation, the deal could be interesting for Iran."

This article has been adapted from German to English.

Edited by: Leah Carter