The head of the UN nuclear watchdog is scheduled to hold talks in Tehran that come amid stalled efforts to revive the Iranian nuclear deal with world powers.
Rafael Grossi, director of the International Atomic Energy Agency (IAEA), is due to meet on September 12 with the new head of the Atomic Energy Organization of Iran, Mohammad Eslami.
It is Grossi's first visit to Iran since hard-line President Ebrahim Raisi took office in August.
Talks between Iran and world powers over limiting Iran's nuclear program in exchange for sanctions relief have been idle since June.
Earlier this month, the IAEA said in a report that Iran had continued to increase its stockpile of highly enriched uranium.
It also said that verification and monitoring activities have been "seriously undermined" since February, after Iran refused to let inspectors access IAEA monitoring equipment.
Western powers must decide whether to push for a resolution criticizing Iran and raising pressure on it for stonewalling the IAEA at next week's meeting of the agency's 35-country board of governors. A resolution could jeopardize the resumption of talks on the deal, as Tehran bristles at such moves.
Under the 2015 deal between Iran and major powers, Tehran agreed to restrictions on its nuclear activities in exchange for the lifting of sanctions.
President Donald Trump pulled the United States out of the deal in 2018, reintroducing painful economic sanctions. Iran responded as of 2019 by breaching many of the deal's core restrictions, like enriching uranium to a higher purity, closer to that suitable for use in nuclear weapons.