The International Atomic Energy Agency (IAEA) was denied access to the TESA Karaj centrifuge component manufacturing workshop contrary to its September 12 agreement with Iran, the agency said in a statement.

"The Director General reiterates that all of the agency's activities referred to in the joint statement for all identified agency equipment and Iranian facilities and locations are indispensable in order to maintain continuity of knowledge," it said.

IAEA Director General Rafael Grossi in his latest report on Iran informed member states that the Islamic republic had granted all other access from September 20-22.

Agency inspectors had been allowed to service monitoring and surveillance equipment and to replace storage media at "all necessary locations" except the TESA Karaj workshop, the statement said.

The IAEA's latest report comes amid stalled negotiations to revive a 2015 landmark agreement scaling back Iran's nuclear programme in exchange for sanctions relief.

That deal started to fall apart in 2018 when the US withdrew from it and reinstated sanctions. Iran in turn again started to ramp up its nuclear activities.

Iran's foreign minister said Friday that the talks to revive the deal would resume "very soon" but the United States responded by saying it wasn't sure what timeframe Tehran had in mind.

The aim of the talks is to bring the US back into the deal and Iran to scale back again its nuclear activities and allow full IAEA access.