Iran has invited a number of nations to a tour of its nuclear facilities. Or at least those that have been in the news. It has, rather ostentatiously, not invited the United States.
This seems to be part of its preparation for talks with those nations on its nuclear program. It's a petty and irrelevant thing to do. The issues that Iran faces on its nuclear program are primarily with the International Atomic Energy Agency and its inspectors. The discussions with the P5+1 group have to do with those issues, but it is the IAEA that must certify Iran's compliance with its agreements.
One of those issues has been the revelation of one undisclosed site after another. Visits to disclosed sites can't take away the suspicion that there may be more undisclosed sites.
Iran is relying on the international news media to blow up a personalized story emphasizing that the United States has not been invited to the party. So far, the New York Times and Washington Post haven't gone that direction in the stories, only the Times headline. But, sadly, I expect to see that sort of commentary.