Talks about reviving the 2015 Iran nuclear deal resume Monday in Vienna after a five-month break and for the first time since a new president took office in Iran.
Like six previous rounds of negotiations, which began in April, the United States is participating indirectly, similar to the 2015 deal, which was known as the Joint Comprehensive Plan of Action. Iran will talk directly with the remaining signatories of the 2015 deal - Britain, China, France, Russia and Germany - with European diplomats shuttling back and forth to consult with the U.S. side.
At stake is the resumption of the agreement that brought limits to Iran's nuclear program lasting between 10 and 15 years in exchange for sanctions relief.
The United States withdrew from the agreement in 2018 during the administration of President Donald Trump, after which Iran began stepping away from its commitments.
To date, Iran has exceeded its agreed limits on the amount of uranium it stockpiles, enriched uranium to higher levels and utilized more advanced centrifuges in its nuclear facilities.
The original agreement came in response to fears that Iran was working to develop nuclear weapons, which Iran has denied, saying its nuclear program is for peaceful purposes such as research and generating power.
Some information for this report came from the Associated Press, Agence France-Presse and Reuters.