( CNN ) -- Top International Atomic Energy Agency officials arrived in Iran Sunday , state media reported , after the head of the United Nations nuclear watchdog expressed fresh concerns that the Islamic republic was trying to develop nuclear weapons . The six-member delegation , including chief inspector Herman Nackaerts , arrived at Tehran 's Imam Khomeini International Airport , Press TV reported . `` We are trying ... to resolve all the outstanding issues with Iran , '' Nackaerts told reporters earlier , as he was about to leave Vienna , Austria , according to Press TV . `` We are looking forward to the start of a dialogue , a dialogue that is overdue . '' A mission to Iran by such a senior team -- which also includes the agency 's second-in-command , Rafael Grossi -- is unusual , the agency said when it announced the visit on Monday . The team is due to be in Iran through Tuesday , the IAEA says . The announcement of the mission came shortly after the European Union imposed a tough round of new sanctions on Iran , aimed at cutting off funding to the country 's nuclear program . The United States and Australia have also ramped up sanctions on Iran in the past week . The United States and its allies think Tehran is trying to develop nuclear weapons . Iran denies it . Speaking Friday at the Davos Forum in Switzerland , energy agency Director General Yukiya Amano told reporters the visit is intended `` to clarify the issues with possible military dimensions . `` We are not very sure whether Iran has declared everything and , therefore , we are not very sure that everything stays in peaceful purpose , '' he said . `` In addition , we have information that Iran has engaged in activities related to the development of nuclear weapons . Therefore , we need to clarify . '' `` The preparations have gone well , but we need to see what actually happens when the mission arrives , '' he said . Inspectors are in and out of the country regularly , an agency spokeswoman said Monday , but a high-level visit of the kind taking place at the end of the month is more unusual . Iran 's envoy to the energy agency said Saturday he was hopeful the trip will `` resolve any ambiguity and show ( our ) transparency and cooperation with the agency . '' `` This trip is aimed at neutralizing enemy plots ... and baseless allegations , and proving the peaceful nature of our nuclear activities , '' Ali Asghar Soltanieh told state-run Islamic Republican News Agency . Amano said that the energy agency proposed the mission , and Iranian authorities `` agreed to accept '' it . But the Islamic news agency reported Nackaerts is traveling at Tehran 's invitation . Iran 's President Mahmoud Ahmadinejad has said he was ready to discuss the program with a group of world powers that have been having on-and-off negotiations with the country over its nuclear ambitions -- including Britain , China , France , Germany , Russia and the United States . The energy agency reported in November that it can no longer verify that the Iranian nuclear program remains peaceful , and Iran is under increasing international pressure to halt its nuclear fuel work . Western sanctions have targeted its currency , the rial , driving up prices for goods within Iran , and the European Union announced Monday that it would stop importing Iranian oil as of July 1 in an effort to starve the country 's nuclear program of funding . In response , an Iranian official said Sunday that Tehran would stop oil exports to `` certain countries , '' soon , according to the state-run Islamic Republic News Agency . Oil Minister Rostam Qassemi made the statement after a cabinet meeting Sunday , as Iranian lawmakers are debating whether to halt oil exports to European countries , IRNA reported .
A six-member International Atomic Energy Agency arrives in Tehran , Iranian media says . The agency head worries that Iran is trying to build nuclear weapons , he says . Iran says its nuclear program is for peaceful purposes . The IAEA chief has said he hopes to trip can `` clarify '' military dimensions of Iran 's program .