Negotiators have made significant progress in the last week or so on reviving the 2015 Iran nuclear deal but very tough issues remain, a senior U.S. State Department official said on Friday, Trend reports citing Reuters.
The U.S. official said he hoped Iran's lead negotiator would return in the coming days to Vienna, where the talks are taking place, "with a positive view" but that even if he did, there were still difficult issues on the table.
"There's been significant progress over the last week or two," the U.S. official told reporters on condition that he not be named. "But at the same time it's important to note that very serious issues remain."