The head of the UN atomic watchdog will visit Tehran on Monday for meetings with senior Iranian officials aimed at improving co-operation on Iran's nuclear activities, the IAEA said. The visit comes amid tensions between the US and its European allies over Washington's bid to maintain an arms embargo on Iran and reimpose UN sanctions dating back to 2006. It will be the first visit to Iran by Rafael Mariano Grossi since he became director general of the International Atomic Energy Agency in December. The IAEA said in a statement on Saturday that Mr Grossi will address Iran's co-operation with the agency and in particular access for its inspectors to certain sites. "My objective is that my meetings in Tehran will lead to concrete progress in addressing the outstanding questions that the agency has related to safeguards in Iran and, in particular, to resolve the issue of access," he said. "I also hope to establish a fruitful and co-operative channel of direct dialogue with the Iranian government which will be valuable now and in the future." Mr Grossi's visit takes place shortly before a September 1 meeting in Vienna of the joint commission on the landmark 2015 deal between Iran and global powers that aims to prevent Tehran from developing a nuclear bomb. The US and European nations are at loggerheads after Washington began the process on Thursday of activating a controversial "snapback" mechanism aimed at restoring UN sanctions on Iran. Britain, France and Germany <a href="https://www.thenational.ae/world/european-statement-sets-out-refusal-to-back-iran-arms-ban-extension-1.1066625">rejected the move</a>, saying it frustrated their efforts to salvage the 2015 accord that US President Donald Trump pulled out of two years ago. Iran has also rejected the move, but the US has stuck to its guns, declaring that a 30-day countdown for the snapback of penalties had begun. The nuclear deal, known as the Joint Comprehensive Plan of Action, or JCPOA, promises Iran economic incentives in exchange for curbs on its nuclear programme. But with the reinstatement of some American sanctions since 2018, Iran's economy has been steadily deteriorating and Tehran has begun violating provisions of the agreement to try to pressure the other countries to do more to offset those sanctions. At the same time, Iran has continued to provide IAEA inspectors with access to its nuclear facilities – one of the major reasons the countries still party to the agreement say it is important to keep it alive.