The UN nuclear watchdog, the International Atomic Energy Agency (IAEA), announced on Wednesday that a technical team will visit Tehran on Sunday aiming to resolve a years-long impasse over an inquiry into undeclared uranium particles found in Iran, AFP reported.
"At the invitation of Iran, an IAEA technical team will be in Tehran on Sunday", an IAEA spokeswoman said.
The December 18 visit is aimed at "addressing the outstanding safeguards issues previously reported", she added.
UN nuclear watchdog chief Rafael Grossi is not expected to visit Iran this time.
The IAEA has long been pressing Iran to provide answers on the presence of undeclared nuclear material found at three sites.
A recent report by the agency concluded there had been "no progress" in the long-standing probe, which has been a key sticking point in talks on a return to the 2015 nuclear deal.
The IAEA’s announcement came hours after Iran said that IAEA officials would visit the country to settle "ambiguities" over claims of secret activities.
Last month, the IAEA board of governors passed a resolution criticizing Iran for its lack of cooperation with the agency.
The impasse over the agency's probe comes as wider talks to revive the 2015 nuclear deal are stalled.
Iran in September announced it had submitted its comments to the US response to the European Union’s draft for reviving the 2015 Iran nuclear deal.
While Iran’s Foreign Ministry spokesperson said at the time that Iran’s response was prepared based on a constructive approach, a senior Biden administration official said the Iranian response "is not at all encouraging.”
A US official later said that the efforts to revive the 2015 Iran nuclear deal have “hit a wall” because of Iran's insistence on the closure of the UN nuclear watchdog's investigations.
The US envoy for Iran, Robert Malley, subsequently said Iran's crackdown on protesters and the sale of drones to Russia have turned the United States' focus away from reviving the nuclear deal.