TEHRAN: The head of the UN nuclear watchdog met Iran's atomic energy chief in Tehran Sunday, hours before a deadline set by the Islamic republic to limit inspections by the agency if US sanctions are not lifted.

The visit comes amid stepped-up efforts between US President Joe Biden's administration, European powers and Iran to salvage the 2015 nuclear deal that has been on the brink of collapse since Donald Trump withdrew from it.

Rafael Grossi, head of the International Atomic Energy Agency (IAEA), arrived in Tehran late Saturday and met with the head of the Iran Atomic Energy Organisation, Ali Akbar Salehi, early Sunday, TV images showed.

The end-of-Sunday deadline, set months ago by Iranian lawmakers, carries the threat of a suspension of some nuclear inspections from Tuesday, but Iran has stressed it will not cease working with the IAEA or expel its inspectors.

Iran has notified the UN body it will suspend "voluntary transparency measures" -- notably inspection visits to non-nuclear sites, including military sites suspected of nuclear-related activity -- if the US fails to lift the sweeping sanctions Trump reimposed in 2018.

"In my opinion, the IAEA's inspection capability will be reduced by about 20-30 percent after the implementation of the parliament's law" on Tuesday, deputy foreign minister Abbas Araghchi said in an interview televised late Saturday night.

"This certainly does not mean withdrawing from the JCPOA," he added, referring to the so-called Joint Comprehensive Plan of Action agreed in 2015 between Iran and the five UN Security Council permanent members and Germany.

Iran's Foreign Minister Mohammad Javad Zarif was due to meet Grossi later on Sunday, Zarif told Iran's English-language Press TV network.

The director of the Vienna-based UN agency was due to hold a press conference on Sunday evening upon returning from Tehran.

Biden has committing to rejoin talks on Tehran's nuclear programme, in a shift away from Trump's policy of "maximum pressure" towards the Islamic republic.

Tehran has repeatedly said it is ready to return to its nuclear commitments, on the condition that Washington makes the first move by lifting the painful sanctions that were reimposed by Trump.

   **- 'Coming days critical' -**

The European Union's political director, Enrique Mora, on Thursday proposed via Twitter an "informal meeting" involving Iran -- and Washington accepted.

State Department spokesman Ned Price said "the United States would accept an invitation from the European Union High Representative to attend a meeting of the P5+1 and Iran to discuss a diplomatic way forward on Iran's nuclear program".

Zarif had previously called for EU foreign policy chief Josep Borrell to "choreograph" action between Washington and Tehran.

Araghchi said Saturday that Iran was considering the EU's proposal but does not consider talks necessary for the US sanctions to be lifted.

"We are reviewing (this) proposal and will decide on it after consultations," he said, adding that Iran was discussing the issue with "friends and allies such as China and Russia".

"But, principally, we believe that America's return to the JCPOA and lifting sanctions, and acting on its commitments, do not require negotiations," he added.

Iran's newspapers on Sunday reflected a range of views regarding Grossi's visit and the impact of the parliament's law.

The ultraconservative Kayhan daily praised the lawmakers' initiative that had "dragged" the IAEA chief to Tehran, calling it a "strategic action" that had made the other parties understand that "breaking a contract is costly".

But the reformist Shargh newspaper appeared pessimistic of the deadline's impact, arguing that Washington had "shown no willingness to return to the agreement".

"There is no prospect of opening up yet," it said, adding that the "coming days are critical" for all parties to the deal.—AFP