Iran and the U.S., holding talks in Rome, will have experts meet to discuss details of a possible deal over Tehran’s rapidly advancing nuclear program, Iran's top diplomat says.

That the talks are even happening represents a historic moment, given the decades of enmity between the two countries since the 1979 Islamic Revolution and the U.S. Embassy hostage crisis.

US and Iranian delegations will gather in Rome Saturday for a second round of high-level talks on Tehran’s nuclear program amid tempered optimism about a diplomatic way forward.