Speaking at the first meeting of the IAEA's board of governors since US President Donald Trump threw the future of the deal in doubt in May with his decision to withdraw, Director General Yukiya Amano said the agency had had access to all sites in Iran that it needed to visit and that "Iran was implementing its nuclear-related commitments".

However, echoing language in the agency's last report on Iran in May, Amano said that "in some cases, there existed room for Iran to provide us with more proactive and timely access, but such cases are not uncommon in safeguard implementation".

While the IAEA itself has not given any more detail on these cases, it is understood that one recent inspection at a research facility was held up -- but still carried out within the necessary time limits.

A senior diplomat in Vienna, where the IAEA is based, said recently that the agency's language was aimed at "encouraging (Iran) to go above and beyond the requirements" of the deal.

Tehran could, for example, invite inspectors to sites they had not demanded access to, the diplomat said.

Asked about the presentation that the Israeli Prime Minister Benjamin Netanyahu made in April on Iran's nuclear programme, Amano said that the agency had "carefully" watched Netanyahu's press conference on the topic and had "an initial exchange of views as a follow-up".

"We have just started to look into the information," Amano said, adding he expected it will take "a long time" to analyse.

Iran's regional arch-foe Israel has long been opposed to the 2015 Joint Comprehensive Plan of Action (JCPOA) and in April Netanyahu unveiled an intelligence trove on Iran's alleged nuclear ambitions.

However he did not present evidence that Iran had actively worked to obtain an atomic weapon since the deal was struck.

The other signatories to the JCPOA have been scrambling to find ways to keep it going since Trump's announcement that he would pull out and reinstate US sanctions.

Last month, a senior Iranian official said Trump's actions had left the landmark accord in "intensive care".

As its price for staying in the deal, Iran has demanded European powers present an "economic package" that would mitigate the effects of US sanctions.

Tehran has threatened to restart its uranium enrichment programme at an "industrial level" if the 2015 pact falls apart.