The UN nuclear watchdog said Friday it had received no reply from Tehran over the possible extension of a temporary agreement covering inspections at Iranian nuclear facilities which expired on Thursday.

The International Atomic Energy Agency (IAEA) said in a statement its director Rafael Grossi had written to Tehran about the matter on 17 June but that "Iran had not replied to his letter or indicated whether it intends to maintain the current arrangement".

Grossi said "an immediate response from Iran is needed in this regard". 

In late February, Iran limited the IAEA's access to nuclear sites it has been monitoring as part of the 2015 deal.

A three-month agreement reached on February 21 allowing some inspections to continue was extended by another month in May.

Under that deal Iran pledged to keep recordings "of some activities and monitoring equipment" and hand them over to the IAEA as and when US sanctions are lifted.

Grossi has described the deal as a "stop-gap measure... as a way to avoid flying completely blind".

The agreement has been in place while Iran and world powers negotiate in Vienna over a possible US return to the landmark 2015 nuclear deal.

The accord has been unravelling ever since former US President Donald Trump withdrew from it in May 2018 and went on to re-impose sanctions against Iran.

Iranian state media on Wednesday quoted Mahmoud Vaezi, chief of staff to Iranian President Hassan Rouhani, as saying that the country's Supreme National Security Council would take a decision on whether to extend the arrangement with the IAEA at its first meeting after the  expiration date.