The head of the UN's International Atomic Energy Agency (IAEA) met with the head of Iran's Atomic Energy Organization in Tehran on Friday amid concerns that the Islamic republic recently increased its uranium enrichment.
Iranian media published photos of IAEA chief Rafael Grossi and Mohammad Eslami.
Grossi wants to negotiate, among other things, more intensive IAEA inspections at nuclear facilities during his visit to Iran, Western diplomats have said. The IAEA chief will stay in Iran until Saturday for the talks.
The negotiations are also about a dispute over the as yet unresolved origin of traces of radioactive material at three sites, according to Tehran.
The Iranian government has previously rejected the IAEA's concerns as groundless. Iran's political leadership is demanding the differences be settled. Observers say the visit is basically about normalizing relations.
Grossi reported on Tuesday that IAEA inspectors had found traces of uranium with a purity level of just under 84% at a plant in Fordo.
A purity level of around 90% is required for nuclear weapons. The IAEA wants to clarify whether the high enrichment level was achieved deliberately or whether it was an unintentional outlier, as Iranian representatives argue.
In 2015, Iran pledged to limit its nuclear programme after the Joint Comprehensive Plan of Action, known as the JCPOA, was negotiated with former US president Barack Obama's administration.
In return, Western sanctions were lifted. The JCPOA was intended to prevent the authoritarian-ruled country from joining the circle of nuclear powers.
Under Obama's successor, former US president Donald Trump, the United States withdrew from the agreement in 2018. Tehran responded by expanding uranium enrichment and restricting IAEA inspections.
Negotiations to revive the agreement are on hold. Iran maintains its nuclear programme is for civilian purposes only.
