The U.S. and Iran have agreed to meet for a third round of talks later this week in Muscat, Oman, after they met in Italy with Omani intermediaries to discuss Iran’s nuclear program on Saturday.

Details of the negotiations have not been released and any concrete progress in ending Iran’s nuclear program remains unclear, though a senior administration official told Fox News that “very good progress” had been made.

“Today, in Rome, over four hours in our second round of talks, we made very good progress in our direct and indirect discussions,” the official said Saturday. “We agreed to meet again next week and are grateful to our Omani partners for facilitating these talks and to our Italian partners for hosting us today.”

 Technicians work inside a uranium conversion facility on March 30, 2005, near Isfahan, Iran. (Getty Images)

“The initiation of expert level track will begin in coming days with a view to hammer out details,” Araghchi said. “After that, we will be in a better position to judge. For now, optimism may be warranted but only with a great deal of caution.”

It remains unclear how this round of negotiations to end Iran’s nuclear program will differ from the original JPCOA, an Obama-era nuclear deal which Trump abandoned during his first term, though the president and other security experts have voiced a sense of urgency in finding a solution in the very near future. 

But according to retired Gen. Jack Keane, a Fox News senior strategic analyst, many security experts are watching these negotiation attempts with “real concern” because “Iran in 2025 is not the Iran in 2015 when that first nuclear deal was made.”

Secretary of State John Kerry, third from left, and other U.S. officials meet with EU and Iranian officials for nuclear talks in Vienna, Austria, June 30, 2015. (Pool/Siamek Ebrahimi/Anadolu Agency/Getty Images)

“The difference is that Iran has the capability to manufacture advanced centrifuges which can enrich uranium from zero to weapons grade in just a matter of weeks,” Keane said.

Essentially, this means the U.S. must not only persuade Iran to get rid of its near-weapons-grade enriched uranium – enough to produce five nuclear weapons if further enriched – but also dismantle its manufacturing capabilities.

“The other thing that is different in 2025 – they have ballistic missiles that can deliver the weapon,” Keane added. “It remains to be seen what’s going to be in the deal.”